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tkaiser

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Posts posted by tkaiser

  1. 6 minutes ago, emk2203 said:

    The fact that they promise mainline kernel, starting from 4.19, actually made me buy it. All ARM devices are sketchy in this regard.

     

    Well, depends solely on the SoC used. I just did some benchmarks with 4.19 on one of my RK3399 devices yesterday: https://forum.armbian.com/topic/8161-swap-on-sbc/?do=findComment&comment=61637

     

    Wrt features I'm not that much interested in (anything that requires adding a display to the boards) I wouldn't count on every feature available with mainline Linux (or Linux at all) regardless of SoC. But honestly I don't know enough about these areas and even managed to spread BS already.

     

  2. 1 hour ago, botfap said:

    Lzo was faster and less cpu intensive overall despite lz4 being better on paper (and from the opinions of almost every internet warrior)

     

    Ok, so another time the same observation. Maybe we should switch back to lzo then already. I feared my test always using the same task is somewhat flawed. At least it's configurable as SWAP_ALGORITHM in /etc/default/armbian-zram-config. But starting with the best default is for sure a good thing prior to next major release when this stuff gets rolled out.

     

    1 hour ago, botfap said:

    Do you know which variant of lzo is being used by Armbian?

     

    Nope. I simply used default kernel settings (and only tested with Rockchip 4.4, mainline 4.14 on NanoPi Fire3 and 4.19 on RK3399). How to configure the specific algorithm?

     

    Edit: another interesting observation: https://bugs.chromium.org/p/chromium/issues/detail?id=584437#c15 I really wonder whether the compression algorithms on ARM use NEON optimizations or not (the performance boost can be huge)

  3. On 9/11/2018 at 7:03 AM, tkaiser said:

    Well, the first thing I would try to improve is replacing the thermal pad with something with a lot better heat conductivity

     

    I did just that:

     

    NanoPi_Fire3_Efficient_Heat_Dissipation.

     

    The thick thermal pad has been removed and replaced with a 15x15mm copper shim (0.8mm height). The grey stuff around the SoC are leftovers from another thermal pad (came with RockPro64) just to prevent shorting things with the heatsink.

     

    I tried to use sbc-bench in thermal testing mode. NanoPi Fire is in upright position (so convection might help a little bit) in a room with 24°C ambient temperature.

    sbc-bench.sh -T 80 ; sbc-bench.sh -t 60

    Problem N° 1: with stock thermal pad I would have to wait endlessly for the SoC to cool down below 60°C (that what 'sbc-bench.sh -t 60' is supposed to do). The board once hot remained at 62°C to 63°C. I had to temporarely switch cpufreq governor to let the CPU cores clock down from 1400 to 400 MHz to get an idle temperature below 60°C again.

     

    Then numbers were as follows:

    1400 MHz:  146.17 sec
    1300 MHz:  148.42 sec
    1200 MHz:       0 sec
    1100 MHz:       0 sec
    1000 MHz:       0 sec
     900 MHz:       0 sec
     800 MHz:       0 sec
     700 MHz:       0 sec
     600 MHz:       0 sec
     500 MHz:       0 sec
     400 MHz:    5.80 sec

    (the 6 seconds on 400 MHz are not result of throttling but me manually switching back to performance cpufreq governor once the real benchmark run started). Full output where you can see how long it took to cool down from 80°C to 60°C: https://pastebin.com/raw/1DDt8yGk

     

    Now with copper shim instead of thermal pad.

     

    Problem N° 2: now it's impossible for the 'pre-heat' run to get above 80°C. I would have to wait endlessly for this so I stopped and ran 'sbc-bench.sh -T 78 ; sbc-bench.sh -t 60' instead to only wait until temperature exceeds 78°C. Full output: https://pastebin.com/raw/a0vmQJ0b

     

    No throttling happened and temperature remained below 80°C. Again it's obvious that thermal pads simply suck when it's about efficient heat dissipation. But I've to admit that I've no idea whether the contact area now with my copper shim is sufficient or thermal pads are the recommended way since with my copper shim now only the very small die area and the copper shim have contact while the area around not.

     

    @mindee can you please shed some light?

     

    Edit: haha, today I realized that I ran with just 4 CPU cores active yesterday when I made my tests due to 'maxcpus=4' set in /boot/armbianEnv.txt (to test for swap efficiency of various approaches). Doesn't change anything wrt thermal conductivity but of course now with all 8 CPU cores active NanoPi Fire3 starts to throttle severely when running heavy stuff but at least with copper shim clockspeeds are much higher compared to thermal pad.

  4. 4 hours ago, gounthar said:

    I may run some tests to help...

     

    Well, if Libre Computer is interested in getting Armbian on their boards at least some developers need samples. And wrt testing: It's a RK3399 thing so almost everything is already known.

     

    Only interesting: how fast is memory access (are different DRAM initialization BLOBs used or not?), how fast is the eMMC and how well works heat dissipation. So iozone and sbc-bench and done.

     

    To me Renegade Elite looks more like an ARM device for a couple of professional use cases (mainly dealing with cameras and imaging) running Android. But it seems enthousiasts are not scared away by costs and want to run Linux for whatever reasons...

     

    Almost forgot: Of course compatibility testing with various USB-C PSUs might be interesting as well. @gounthar which USB-C chargers do you own? 'Good' ones from this list?

  5. Little update: In the meantime I also tested with the really fast Samsung 16GB eMMC 5.1 on NanoPC-T4 (again crippled down to a quad-core A53 at 800 MHz). The board runs off the NVMe SSD, I mounted the eMMC as an ext4 partition, put there ARM's ComputeLibrary install and the swapfile on and fired up the test again. First post above is updated.

     

    With 4 GB RAM and no swap 100:39 minutes, with swapping on the fast NVMe SSD 118:47 and just 133:34 on the eMMC:

              w/o    nvme     lzo     lz4    emmc    usb2    usb3     hdd    sd card
    real	100m39  118m47  125m26  127m46  133m34  146m49  154m51  481m19   1151m21

    That's impressive. But this Samsung eMMC 5.1 on NanoPC-T4 (and also on ODROID-N1) is most probably the fastest eMMC we get on SBC today (see benchmark numbers). And still zram is faster and we get 'more RAM' for free (since swap on flash media contributes to the medium wearing out of course)

     

     

  6. On 9/10/2018 at 12:32 AM, tkaiser said:

    Next test: RK3399 with unlocked performance (all 6 CPU cores active at usual clockspeeds: 1.5/2.0GHz)

    
              w/o     nvme     lzo/2    lzo/6    lz4/2    lz4/6
    real	 31m55    40m32    41m56    41m38    43m57    44m26
    user    184m16   194m58   200m37   202m20   195m17   197m51
    sys       6m04    16m17    25m02    23m14    40m59    42m15

     

     

    All those tests I did before were done with Rockchip's 4.4 kernel.

     

    Since stuff in the kernel improves over time now let's test with brand new 4.19.0-rc1. I just did a quick build (with default device tree that limits maximum cpufreq to 1.8 GHz on the big and 1.4 GHz on the little cores) and only tested performance without swapping and zram based swap with the available algorithms (more recent kernels provide more compression algorithms to choose from):

              w/o      lzo      lz4      zstd    lz4hc
    real	 29m11    35m58    36m59    48m38    58m55
    user    167m59   177m24   175m22   182m02   173m57
    sys       5m32    21m10    22m59    69m35   123m46

     

    Results:

    • More recent kernel --> better results. Even with lower clockspeeds (1.8/1.4 GHz vs. 2.0/1.5 GHz) the test with kernel 4.19 runs 8% faster. So at same clockspeed this would result even in ~10% better performance
    • Performance drop with zram/lzo compared to no swap with 4.4 was 31%. With 4.19 it's just 23%. So efficiency/performance of the zram implementation itself also improved a lot
    • Again lzo is slightly faster than lz4, both zstd and lz4hc are no good candidates for this use case (but zstd is a great candidate for Armbian's new ramlog approach since it provides higher compression -- more on this later)

    In other words: with mainline kernel it makes even more sense to swap to a compressed block device in RAM since performance further increased. With this specific use case (large compile job) the performance drop when running out of memory and the kernel starting to swap to zram is below the 25% margin which is just awesome :)

     

  7. 19 hours ago, sakibnaz said:

    Do you know how the performance of 3328 Boards like Rock64 for USB 3.0 Data?

     

    It's all there, just use the search functionality this forum provides:

     

     

  8. On 9/9/2018 at 11:30 AM, gounthar said:

    only one choice for eMMC, which is the 128GB

     

    Honestly: if I have a RK3399 device and want 128 GB storage I choose something different. I ordered a cheap DRAM less NVMe SSD for 40€ (VAT/shipping included),  inserted it into the M.2 slot, transferred the rootfs as easy as always with nand-sata-install and now my NanoPC-T4 runs directly off the NVMe SSD.

     

    I've no doubt that the eMMC performs nicely. But I doubt it's as fast as an NVMe SSD and what I like the most with SSDs: the good ones tell you when they start to wear out:

    root@nanopct4:/home/tk# smartctl -x /dev/nvme0n1
    smartctl 6.6 2016-05-31 r4324 [aarch64-linux-4.4.153-rk3399] (local build)
    Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org
    
    === START OF INFORMATION SECTION ===
    Model Number:                       TS128GMTE110S
    Serial Number:                      AC2153AAE531202E0165
    Firmware Version:                   R0515A0
    PCI Vendor/Subsystem ID:            0x126f
    IEEE OUI Identifier:                0x000000
    Controller ID:                      1
    Number of Namespaces:               1
    Namespace 1 Size/Capacity:          128,035,676,160 [128 GB]
    Namespace 1 Formatted LBA Size:     512
    Local Time is:                      Mon Sep 10 18:38:24 2018 UTC
    Firmware Updates (0x14):            2 Slots, no Reset required
    Optional Admin Commands (0x0006):   Format Frmw_DL
    Optional NVM Commands (0x005f):     Comp Wr_Unc DS_Mngmt Wr_Zero Sav/Sel_Feat *Other*
    Maximum Data Transfer Size:         64 Pages
    Warning  Comp. Temp. Threshold:     70 Celsius
    Critical Comp. Temp. Threshold:     80 Celsius
    
    Supported Power States
    St Op     Max   Active     Idle   RL RT WL WT  Ent_Lat  Ex_Lat
     0 +     9.00W       -        -    0  0  0  0        0       0
    
    Supported LBA Sizes (NSID 0x1)
    Id Fmt  Data  Metadt  Rel_Perf
     0 +     512       0         0
    
    === START OF SMART DATA SECTION ===
    SMART overall-health self-assessment test result: PASSED
    
    SMART/Health Information (NVMe Log 0x02, NSID 0x1)
    Critical Warning:                   0x00
    Temperature:                        28 Celsius
    Available Spare:                    100%
    Available Spare Threshold:          10%
    Percentage Used:                    0%
    Data Units Read:                    110,342 [56.4 GB]
    Data Units Written:                 289,050 [147 GB]
    Host Read Commands:                 11,897,227
    Host Write Commands:                22,892,268
    Controller Busy Time:               126
    Power Cycles:                       10
    Power On Hours:                     1
    Unsafe Shutdowns:                   4
    Media and Data Integrity Errors:    0
    Error Information Log Entries:      0
    Warning  Comp. Temperature Time:    0
    Critical Comp. Temperature Time:    0

     

    The 'Percentage Used' line is the important one. As long as this is below 90 everything's fine. An eMMC will die suddenly without any prior warning...

  9. 5 hours ago, Tido said:

    systemctl disable NetworkManager.service

     

    Not a good idea as Zador already explained: https://forum.armbian.com/topic/6104-network-manager-woes/?do=findComment&comment=46901 -- people not able to cope with NM should better entirely remove it.

     

    2 hours ago, gleam said:

    So I once will have DHCP never again. Never, never! 

     

    Interesting way to 'spend' your own time. One of the first things I always do at new customers is to stop configuring statically assigned addresses on each server machine to centrally configured static IP addresses via DHCP. If name resolution is set up correctly not even this would be necessary since names are consistent and addresses don't matter anyway...

  10. 5 hours ago, mindee said:

    very helpful for someone who want to know about the NVME SSD real performance on RK3399 boards

     

    In fact I bought cheap since I got the NVMe SSD for less than 40 bucks on sale. My small TS128GMTE110S has soldered only 2 flash chips on it, if the maximum would be present (8) then it would be much much faster since all modern SSD controllers make heavy use of paralellisms (the more flash chips the faster).

     

    I did a quick iozone test with kernel 4.4 and results look not that great compared to an EVO 960 for example.

     
    
    Transcend TS128GMTE110S ext4                                  random    random
                  kB  reclen    write  rewrite    read    reread    read     write
              102400       4    81473   115499   145683   147298    40272    82992
              102400      16   179264   249123   293189   293318   111869   246077
              102400     512   578704   579090   829601   832798   658995   567873
              102400    1024   585086   577757   928864   935910   789642   565868
              102400   16384   527840   531048  1045632  1056965  1031390   546275
             2048000   16384   544678   549905  1064665  1064439  1039331   545381

     

     

    But that's not relevant since the protocol makes the difference. NVMe has been invented in this century and not the last as all the other storage protocols we use today. And this makes a real difference since NVMe has been developed with accessing flash storage efficiently in mind. All the other protocols we might use (including SATA) were designed decades ago for way slower storage and all do bottleneck access to fast flash.

     

    With swap on the NVMe SSD the maximum %iowait percentage according to iostat monitoring was 0.37%. That's 70 times less compared to up to 25.07% with USB3!

  11. Next test: RK3399 with unlocked performance (all 6 CPU cores active at usual clockspeeds: 1.5/2.0GHz)

              w/o     nvme     lzo/2    lzo/6    lz4/2    lz4/6
    real	 31m55    40m32    41m56    41m38    43m57    44m26
    user    184m16   194m58   200m37   202m20   195m17   197m51
    sys       6m04    16m17    25m02    23m14    40m59    42m15

    Full test output:

     
    
    Without Swap:
    
    real	31m55.360s
    user	184m16.317s
    sys	6m3.999s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              96.78    0.00    3.11    0.00    0.00    0.11
              96.56    0.00    3.30    0.00    0.00    0.14
              11.57    0.00    0.42    0.00    0.00   88.01
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1           0.56         0.09        36.40         80      32758
    mmcblk1           1.53         6.29        95.42       5664      85876
    mmcblk1           0.14         0.26        29.38        232      26440
    
    
    
    
    
    lzo 2 streams:
    
    real	41m56.261s
    user	200m36.964s
    sys	25m2.247s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              79.01    0.00   20.70    0.04    0.00    0.25
              83.46    0.00   16.40    0.00    0.00    0.14
              61.40    0.00   17.19    0.01    0.00   21.40
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    zram1         10000.57     15515.19     24487.10   13963672   22038392
    zram2          9994.63     15491.28     24487.23   13942156   22038508
    zram1         10381.19     17556.42     23968.32   15800952   21571732
    zram2         10378.70     17546.46     23968.32   15791988   21571732
    zram1          9469.21     16759.32     21117.53   15083392   19005776
    zram2          9455.55     16704.60     21117.59   15034136   19005828
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1          83.01      8366.31        33.08    7529680      29776
    mmcblk1          38.71      2303.10        58.27    2072816      52444
    mmcblk1          46.68      2686.10        50.05    2417489      45048
    
    
    
    
    
    
    lzo 6 streams:
    
    real	41m38.302s
    user	202m20.016s
    sys	23m14.408s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              83.18    0.00   16.71    0.00    0.00    0.11
              82.59    0.00   17.29    0.01    0.00    0.11
              59.98    0.00   16.90    0.01    0.00   23.11
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    zram1          3039.69      4346.14      7812.62    3911524    7031360
    zram2          3040.84      4350.74      7812.63    3915668    7031364
    zram3          3038.73      4342.47      7812.44    3908220    7031196
    zram4          3039.70      4346.43      7812.39    3911784    7031148
    zram5          3038.88      4342.94      7812.59    3908648    7031328
    zram6          3040.02      4347.62      7812.47    3912860    7031220
    zram1          3416.83      5791.84      7875.48    5212656    7087936
    zram2          3417.75      5795.52      7875.49    5215968    7087944
    zram3          3419.16      5801.10      7875.53    5220992    7087980
    zram4          3417.88      5795.81      7875.70    5216232    7088132
    zram5          3418.87      5799.86      7875.61    5219872    7088048
    zram6          3419.90      5804.16      7875.44    5223740    7087896
    zram1          3060.02      5409.21      6830.87    4868344    6147848
    zram2          3059.34      5406.76      6830.61    4866136    6147616
    zram3          3059.39      5406.96      6830.61    4866316    6147616
    zram4          3060.38      5410.83      6830.70    4869800    6147696
    zram5          3060.49      5411.10      6830.87    4870040    6147848
    zram6          3059.70      5407.84      6830.96    4867112    6147932
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1          52.03      3429.48        32.36    3086532      29120
    mmcblk1          37.18      2246.65        58.60    2021988      52740
    mmcblk1          47.53      2735.41        52.83    2461900      47544
    
    
    
    
    
    
    lz4 2 streams:
    
    real	43m57.637s
    user	195m17.556s
    sys	40m59.904s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              77.08    0.00   22.16    0.03    0.00    0.73
              75.15    0.00   23.91    0.02    0.00    0.92
              65.67    0.00   25.35    0.03    0.00    8.94
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    zram1          8801.74     12553.56     22653.41   11298200   20388072
    zram2          8800.08     12547.31     22653.00   11292580   20387704
    zram1         11100.47     18802.53     25599.34   16922840   23040176
    zram2         11099.44     18798.44     25599.32   16919156   23040156
    zram1         10362.92     18539.87     22911.82   16685884   20620640
    zram2         10355.76     18511.28     22911.76   16660152   20620584
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1          66.22      4788.56        31.21    4309700      28092
    mmcblk1          57.70      3918.69        57.91    3526936      52124
    mmcblk1          66.55      3865.90        57.75    3479308      51976
    
    
    
    
    
    
    lz4 6 streams:
    
    real	44m26.940s
    user	197m51.586s
    sys	42m15.525s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              77.44    0.00   22.18    0.02    0.00    0.35
              75.06    0.00   24.54    0.01    0.00    0.38
              68.29    0.00   26.81    0.02    0.00    4.88
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    zram1          2866.07      4112.82      7351.47    3701580    6616400
    zram2          2866.50      4114.47      7351.54    3703064    6616464
    zram3          2866.32      4113.75      7351.52    3702416    6616444
    zram4          2868.42      4122.26      7351.44    3710072    6616372
    zram5          2865.52      4110.65      7351.45    3699624    6616380
    zram6          2867.04      4116.73      7351.44    3705100    6616368
    zram1          3610.06      6068.57      8371.69    5461832    7534688
    zram2          3608.80      6063.51      8371.70    5457276    7534700
    zram3          3608.88      6063.82      8371.70    5457560    7534700
    zram4          3612.11      6076.78      8371.65    5469228    7534652
    zram5          3608.69      6062.87      8371.88    5456704    7534856
    zram6          3609.15      6064.71      8371.88    5458364    7534856
    zram1          3628.46      6460.98      8052.86    5814944    7247656
    zram2          3626.32      6452.34      8052.93    5807168    7247720
    zram3          3626.74      6454.27      8052.68    5808912    7247492
    zram4          3627.31      6456.32      8052.91    5810752    7247700
    zram5          3627.74      6458.25      8052.71    5812488    7247520
    zram6          3629.89      6466.64      8052.92    5820044    7247708
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1          64.98      4413.62        30.87    3972300      27780
    mmcblk1          56.31      3752.78        59.29    3377580      53364
    mmcblk1          67.02      4039.19        58.18    3635312      52360
    
    
    
    
    
    NVMe SSD:
    
    real	40m32.985s
    user	194m58.775s
    sys	16m17.506s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              87.55    0.00   11.60    0.62    0.00    0.23
              85.85    0.00   11.29    2.42    0.00    0.45
              85.85    0.00   11.29    2.42    0.00    0.45
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    nvme0n1       10178.30     12957.70     27755.50   11662060   24980224
    nvme0n1       12027.94     22808.95     25302.80   20528052   22772516
    nvme0n1       12027.94     22808.95     25302.80   20528052   22772516
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1          44.03      2983.29        31.68    2684992      28508
    mmcblk1          22.29       930.41        17.25     837372      15524
    mmcblk1          22.29       930.41        17.25     837372      15524

     

     

     

    For obvious reasons I did not test the crappy variants again (HDD, SD card, USB attached anything). So we're only looking at performance without swap, swap on NVMe SSD and zram.

     

    RK3399 when allowed to run at full speed finishes the same compile job in less than 32 minutes. Swap on NVMe SSD increases time by almost 30% now. I now also compared whether the count of zram devices makes a difference (still on RK's 4.4 kernel). Still lzo outperforms lz4 (which is irritating since everyone tells you lz4 would be an improvement over lzo) but there is no clear answer about count of zram devices (in fact the kernel uses 1-n streams to access each device so with modern kernels even a single zram device should suffice since kernel takes care of distributing the load accross all the CPU cores)

  12. This is some more research based on prior efforts.

     

    The goal is to make more efficient use of available RAM. If the system runs low on memory only two options are possible: either the kernel invokes the oom-killer to quit tasks to free memory (oom --> out of memory) or starting to swap.

     

    Swap is a problem if it happens on slow media. 'Slow' media usually describes the situation on SBC. 'Average' SD cards (not A1 rated) are slow as hell when it's about random IO performance. So swapping is usually something that should be avoided. But... technology improves over time.

     

    In Linux we're able to swap not only to physical storage but since a few years also to compressed memory. If you want to get the details simply do a web search for zram or check Wikipedia first..

     

    Test setup is a NanoPC-T4 equipped with 4 GB RAM (RK3399 based so a big.LITTLE design with 2xA72 and 4xA53). I crippled the board down to being a quad-core A53 running at 800 MHz where I can easily switch between 4GB RAM and lower numbers: Adding 'mem=1110M maxcpus=4' to kernel cmdline results in the A72 cores being inactive, the kernel only using 1 GB DRAM and for whatever reasons cpufreq scaling not working so the RK3399 statically being clocked at 808 MHz. All tests done with RK's 4.4 (4.4.152).

     

    This test setup is meant as 'worst case possible'. A quad-core A53 at 800 MHz is more or less equivalent to a quad-core A7 running at ~1000-1100 MHz. So we're trying to test with the lower limit.

     

    I used a compile job that requires up to 2.6 GB RAM to be built (based on this blog post). The task is to build ARM's Compute Library which involves swapping on systems with less than 3 GB memory. Let's have a look:

     

    In the following I tried a couple of different scenarios: Swap on physical media and also two different zram algorithms:

     

    • w/o: no swapping happened since board booted with full 4GB RAM active
    • nvme: Transcend TS128GMTE110S SSD in M.2 slot, link is established at x4 Gen2
    • emmc: the 16GB ultra fast Samsung eMMC 5.1 on NanoPC-T4
    • usb2: Samsung EVO840 SSD in JMS567 disk enclosure, attached to USB2 port (UAS works)
    • usb3: Samsung EVO840 SSD in JMS567 disk enclosure, attached to USB3 port (UAS works)
    • hdd: Samsung HM500JI 2.5" HDD in JMS567 disk enclosure, attached to USB2 port (UAS works)
    • sd card: 'average' SanDisk 8 GB SD card (not A1 rated so horribly low random IO performance)
    • lzo: zram with lzo as compression algorithm
    • lz4: zram with lz4 as compression algorithm
       

    And the numbers are:

              w/o    nvme     lzo     lz4    emmc    usb2    usb3     hdd    sd card
    real	100m39  118m47  125m26  127m46  133m34  146m49  154m51  481m19   1151m21
    user    389m48  415m38  405m39  402m52  415m38  415m29  407m18  346m28    342m49
    sys      11m05   29m37   36m14   60m01   34m35   66m59   65m44   23m05    216m25

    You need to look at the 1st row: that's the time the whole job took. For more details consult the 'time' manual page.

     

    In other words: When limiting the RK3399 on NanoPC-T4 to just the four A53 cores running at 800 MHz the compile job takes 100 minutes with 4 GB RAM. As soon as we limit the available RAM to 1 GB swapping has to occur so it gets interesting how efficient the various approaches are:

     

    • NVMe SSD is the fastest option. Performance drop only 18%. That's due to NVMe being a modern storage protocol suited for modern (multi-core) CPUs. Problem: there's no PCIe and therefore no NVMe on the majority of SBC
    • Zram with both lzo and lz4 algorithms performs more or less the same (interestingly lzo slightly faster)
    • Slightly slower: the fast Samsung eMMC 5.1
    • Surprisingly the EVO840 SSD connected via USB2 performs better than connected via USB3 (some thoughts on this)
    • Using a HDD for swap is BS (and was BS already the last 4 decades but we had no alternative until SSDs appeared). The compile job needs almost 5 times longer to complete since all HDD suck at random IO
    • Using an average SD card for swap is just horrible. The job that finished within 100 minutes with 4 GB DRAM available took over 19 HOURS with swap on an average SD card (please note that today usual A1 rated SD cards are magnitudes faster and easily outperform HDDs)

     

    Summarizing: NVMe SSDs are no general option (since only available on some RK3399 boards). Swap on HDD or SD card is insane. Swap on USB connected SSDs performs ok-ish (~1.5 times slower) so the best option is to use compressed DRAM. We get a performance drop of just 25% at no additional cost. That's amazing.

     

    The above numbers were 'worst case'. That's why I crippled the RK3399 to a slow performing quad-core A53. You get the idea how 'worse' zram might be on the slowest SBCs Armbian runs on (I know that there are still the boring Allwinner A20 boards around -- yep, they're too slow for this).

     

    When I did all this boring test stuff I always recorded the environment using 'iostat 1800' (reports every 30 minutes what really happened and shows in detail how much data has been transferred and on which the CPU cores spent time). Quite interesting to compare %user, %sys and especially %iowait percentages:

     
    
    Without swap:
    
    real	100m39.355s
    user	389m48.308s
    sys	11m5.366s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              97.14    0.00    2.81    0.00    0.00    0.05
              98.11    0.00    1.89    0.00    0.00    0.00
              96.49    0.00    3.51    0.00    0.00    0.00
              33.63    0.00    1.17    0.00    0.00   65.20
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1           0.39         6.19        15.34      11136      27604
    mmcblk1           0.12         0.01         7.08         24      12748
    mmcblk1           0.29         0.04        29.12         76      52408
    mmcblk1           0.15         0.16        17.47        280      31444
    
    
    
    
    
    
    
    128 GB NVMe SSD (Transcend TS128GMTE110S)
    
    real	118m47.028s
    user	415m38.041s
    sys	29m37.947s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              90.17    0.00    9.83    0.00    0.00    0.00
              89.09    0.00   10.65    0.24    0.00    0.02
              89.06    0.00   10.87    0.06    0.00    0.01
              79.83    0.00   13.75    0.37    0.00    6.05
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    nvme0n1        3531.51      4049.97     10076.08    7290020   18137140
    nvme0n1        4389.70      6759.53     10799.27   12167156   19438688
    nvme0n1        4196.89      7548.11      9239.46   13586596   16631036
    nvme0n1        5397.18      7772.77     13815.96   13990984   24868736
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1           8.60       494.36        15.36     889860      27656
    mmcblk1           5.43       300.62         5.71     541120      10276
    mmcblk1           7.35       332.49        29.08     598480      52336
    mmcblk1          11.18       587.00        20.49    1056608      36876
    
    
    
    
    
    
    Samsung eMMC 5.1
    
    real	133m34.405s
    user	415m38.955s
    sys	34m35.487s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              86.06    0.00    9.33    4.02    0.00    0.59
              82.91    0.00   11.93    4.61    0.00    0.54
              78.06    0.00   13.79    7.60    0.00    0.55
              79.67    0.00   12.85    6.67    0.00    0.81
              23.34    0.00    4.78    5.33    0.00   66.55
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1         885.85      3661.18      7399.21    6590168   13318660
    mmcblk1        1525.72      5780.62      7345.17   10405124   13221300
    mmcblk1        2074.55      7532.86      6865.80   13559216   12358516
    mmcblk1        1465.59      5757.48      7218.02   10363516   12992516
    mmcblk1         768.81      2683.68      3888.00    4830624    6998408
    
    
    
    
    
    Samsung EVO840 USB3 (Class=Mass Storage, Driver=uas, 5000M)
    
    real	154m51.541s
    user	407m18.963s
    sys	65m44.394s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              83.58    0.00   12.39    3.89    0.00    0.14
              75.49    0.00   16.36    7.95    0.00    0.20
              54.74    0.00   19.54   25.07    0.00    0.65
              74.57    0.00   16.33    8.83    0.00    0.27
              51.38    0.00   22.86   24.88    0.00    0.88
               5.81    0.00    1.01    0.57    0.00   92.60
              
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    sda             899.99      3277.29      7391.12    5899448   13304748
    sda            1771.87      4602.59      5641.83    8284336   10154892
    sda            2859.21      7020.32      7443.85   12636572   13398932
    sda            1627.26      4463.28      4558.92    8033988    8206140
    sda            2986.07      8075.17     10204.91   14535304   18368832
    sda             114.34       433.28       234.57     779896     422224
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1           8.76       449.59        14.97     809300      26944
    mmcblk1           6.06       225.07         4.76     405108       8564
    mmcblk1           6.22       212.92         4.06     383248       7304
    mmcblk1           7.90       290.09        28.89     522164      52008
    mmcblk1           8.65       373.69         4.33     672648       7796
    mmcblk1           0.74        25.53        15.89      45956      28596
    
    
    
    
    
    
    
    Samsung EVO840 USB2 (Class=Mass Storage, Driver=uas, 480M)
    
    real	146m49.211s
    user	415m29.511s
    sys	66m59.827s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              82.26    0.00   11.60    5.52    0.00    0.63
              77.11    0.00   16.94    5.68    0.00    0.27
              67.59    0.00   19.14   12.92    0.00    0.35
              78.39    0.00   18.05    3.50    0.00    0.07
              44.69    0.00   13.18   15.43    0.00   26.70
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    sda             875.49      3208.80      6997.15    5775896   12595008
    sda            1791.04      4718.25      5574.88    8493692   10035784
    sda            2491.66      6055.81      6341.38   10900164   11414168
    sda            1844.43      5053.24      4258.27    9095928    7664972
    sda            1854.93      4253.01      5503.57    7655424    9906428
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1           5.74       360.25        14.36     648456      25856
    mmcblk1           3.96       176.13         4.72     317068       8504
    mmcblk1           5.94       173.85         4.32     312916       7776
    mmcblk1           6.75       182.92         7.72     329256      13888
    mmcblk1           6.43       259.09        39.36     466356      70856
    
    
    
    
    
    
    
    SAMSUNG HM500JI USB2 (Class=Mass Storage, Driver=uas, 480M)
    
    real	481m19.903s
    user	346m28.221s
    sys	23m5.888s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              62.34    0.00    5.30   26.52    0.00    5.84
              47.05    0.00    3.66   45.03    0.00    4.27
              30.16    0.00    2.33   60.95    0.00    6.55
              37.39    0.00    3.19   52.27    0.00    7.15
              47.45    0.00    4.44   42.35    0.00    5.76
              16.43    0.00    1.47   52.25    0.00   29.85
               1.86    0.00    0.72   46.10    0.00   51.32
               2.40    0.00    0.70   54.83    0.00   42.08
               1.83    0.00    0.60   52.51    0.00   45.06
               2.38    0.00    0.61   54.73    0.00   42.28
               3.41    0.00    0.72   60.17    0.00   35.70
               2.12    0.00    0.60   53.32    0.00   43.97
               2.89    0.00    0.58   58.69    0.00   37.84
               3.39    0.00    0.68   60.29    0.00   35.63
               3.35    0.00    0.65   52.47    0.00   43.53
              24.89    0.00    0.51   23.60    0.00   51.00
               0.46    0.00    0.05    0.43    0.00   99.05
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    sda             202.08      1103.73      2568.98    1987224    4625352
    sda             210.18       823.92       759.15    1483160    1366572
    sda             251.15       614.00      1118.09    1105060    2012324
    sda             243.75       637.75       562.81    1147928    1013036
    sda             242.72       535.27       757.41     963668    1363592
    sda             179.62       584.52       240.07    1052216     432164
    sda             183.93       595.70       468.54    1072096     843248
    sda             196.65       569.87       352.33    1025772     634192
    sda             185.96       533.97       285.93     961144     514676
    sda             190.90       503.49       303.76     906288     546772
    sda             189.79       479.81       467.16     863660     840892
    sda             174.72       498.87       315.20     897960     567356
    sda             178.52       462.67       278.10     832800     500588
    sda             192.74       449.58       405.82     809244     730484
    sda             183.37       497.22       350.15     894996     630268
    sda              74.32       312.27        14.20     562084      25560
    sda               2.92        12.27         0.00      22092          0
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1           5.04       331.77        14.07     597332      25332
    mmcblk1           0.85        27.32         5.08      49172       9144
    mmcblk1           0.47        45.07         1.68      81124       3032
    mmcblk1           1.67        41.63         5.73      74924      10312
    mmcblk1           3.30        79.95         5.89     143936      10612
    mmcblk1           0.99        24.50         2.61      44108       4692
    mmcblk1           0.06         8.91         0.48      16036        860
    mmcblk1           0.11        10.18         1.02      18328       1828
    mmcblk1           0.08        10.23         1.04      18416       1876
    mmcblk1           0.03         4.24         0.98       7640       1764
    mmcblk1           0.02         3.66         0.45       6580        812
    mmcblk1           0.05         7.84         1.00      14120       1804
    mmcblk1           0.02         2.26         0.45       4068        812
    mmcblk1           0.03         4.56         0.98       8216       1764
    mmcblk1           0.09        15.84         1.41      28520       2536
    mmcblk1           0.69        23.72        20.68      42696      37220
    mmcblk1           0.26         6.97        22.35      12544      40232
    
    
    
    
    
    
    
    zram lz4 4 streams:
    
    real	127m46.928s
    user	402m52.389s
    sys	60m1.737s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              84.16    0.00   15.81    0.00    0.00    0.02
              81.10    0.00   18.89    0.00    0.00    0.01
              76.31    0.00   23.68    0.00    0.00    0.01
              79.77    0.00   20.22    0.00    0.00    0.01
              16.56    0.00    8.59    0.01    0.00   74.85
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    zram1          1203.30      1641.51      3171.71    2954732    5709104
    zram2          1202.68      1638.97      3171.76    2950160    5709196
    zram3          1203.74      1643.14      3171.81    2957672    5709288
    zram4          1202.88      1639.80      3171.70    2951664    5709096
    zram1          1634.75      2491.59      4047.41    4485068    7285668
    zram2          1632.13      2481.02      4047.48    4466040    7285792
    zram3          1632.28      2481.82      4047.32    4467468    7285496
    zram4          1633.93      2488.36      4047.37    4479248    7285592
    zram1          2142.44      3778.25      4791.51    6800844    8624712
    zram2          2141.56      3774.83      4791.39    6794700    8624500
    zram3          2141.69      3775.36      4791.42    6795640    8624556
    zram4          2142.77      3779.59      4791.50    6803260    8624692
    zram1          1714.65      2936.11      3922.50    5285296    7060884
    zram2          1713.89      2933.00      3922.56    5279696    7061000
    zram3          1712.34      2926.74      3922.62    5268420    7061116
    zram4          1714.12      2933.77      3922.69    5281088    7061232
    zram1           755.08      1467.73      1552.57    2641884    2794600
    zram2           756.14      1472.05      1552.53    2649652    2794528
    zram3           754.55      1465.77      1552.42    2638356    2794328
    zram4           755.22      1468.43      1552.46    2643152    2794400
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1          16.72      1025.73        15.19    1846324      27340
    mmcblk1          17.52       957.67         6.43    1723876      11572
    mmcblk1          21.79      1547.45        26.22    2785408      47188
    mmcblk1          18.02       970.77         7.58    1747492      13652
    mmcblk1          12.51       803.49        26.94    1446264      48500
    
    
    
    
    
    
    
    zram lzo 4 streams:
    
    real	125m26.180s
    user	405m39.383s
    sys	36m14.588s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              85.31    0.00   14.63    0.00    0.00    0.05
              82.56    0.00   17.44    0.00    0.00    0.00
              80.95    0.00   19.05    0.00    0.00    0.00
              79.52    0.00   20.47    0.00    0.00    0.01
              11.89    0.00    5.46    0.00    0.00   82.65
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    zram1          1174.74      1582.76      3116.19    2848960    5609136
    zram2          1174.93      1583.45      3116.27    2850208    5609284
    zram3          1175.11      1584.21      3116.24    2851580    5609232
    zram4          1174.92      1583.52      3116.15    2850328    5609072
    zram1          1588.69      2414.99      3939.76    4346988    7091564
    zram2          1589.01      2416.06      3939.99    4348900    7091976
    zram3          1588.51      2414.16      3939.86    4345492    7091748
    zram4          1588.29      2413.34      3939.81    4344016    7091660
    zram1          1816.51      3200.85      4065.19    5761560    7317376
    zram2          1815.69      3197.45      4065.31    5755436    7317592
    zram3          1816.19      3199.44      4065.32    5759020    7317620
    zram4          1816.44      3200.38      4065.37    5760724    7317700
    zram1          1823.10      3125.61      4166.79    5626100    7500224
    zram2          1821.87      3120.63      4166.85    5617132    7500332
    zram3          1822.11      3121.60      4166.83    5618876    7500288
    zram4          1822.79      3124.31      4166.83    5623760    7500292
    zram1           517.68       987.91      1082.82    1778232    1949072
    zram2           517.41       986.80      1082.82    1776248    1949084
    zram3           517.20       985.93      1082.87    1774680    1949168
    zram4           517.13       985.70      1082.82    1774256    1949072
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1          12.29       782.37        13.75    1408268      24752
    mmcblk1          10.81       635.53         6.22    1143952      11188
    mmcblk1          14.39       921.31        26.93    1658368      48476
    mmcblk1          14.46       857.51         7.68    1543516      13828
    mmcblk1           5.61       351.26        20.07     632264      36120
    
    
    
    
    
    
    
    zram lzo 1 stream:
    
    real	124m52.403s
    user	397m20.110s
    sys	58m55.228s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              84.59    0.00   15.28    0.00    0.00    0.13
              81.48    0.00   18.35    0.00    0.00    0.18
              79.98    0.00   19.84    0.00    0.00    0.17
              76.64    0.00   22.98    0.00    0.00    0.38
              10.40    0.00    5.06    0.00    0.00   84.54
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    zram1          4558.09      6483.94     11748.41   11671812   21148436
    zram1          6377.26     10079.11     15429.92   18142504   27774004
    zram1          7050.71     12673.06     15529.80   22811500   27953632
    zram1          7258.40     12565.52     16468.06   22617944   29642512
    zram1          1644.30      3404.62      3172.57    6128356    5710652
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk1          15.91       968.35        16.16    1743132      29092
    mmcblk1          15.08       852.01         5.87    1533628      10568
    mmcblk1          17.93      1064.32        26.88    1915772      48376
    mmcblk1          18.86      1036.18         9.54    1865128      17168
    mmcblk1           8.58       494.16        22.66     889484      40780
    
    
    
    
    
    
    SD card:
    
    real	1151m21.149s
    user	342m49.658s
    sys	216m25.202s
    
    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
              11.12    0.00    1.60   80.44    0.00    6.83
               9.03    0.00    1.71   78.10    0.00   11.15
              10.69    0.00    1.42   82.05    0.00    5.84
              21.97    0.00    1.34   70.34    0.00    6.35
               9.90    0.00    1.97   69.94    0.00   18.18
               0.35    0.00    0.83   88.24    0.00   10.57
               2.14    0.00    1.50   81.17    0.00   15.20
               2.68    0.00    1.25   81.60    0.00   14.47
               2.87    0.00    1.10   84.92    0.00   11.11
               8.89    0.00    2.19   77.69    0.00   11.23
               3.54    0.00    1.47   84.79    0.00   10.21
              10.19    0.00    2.91   76.93    0.00    9.96
              10.22    0.00    3.20   78.63    0.00    7.96
               8.12    0.00    4.10   73.85    0.00   13.93
               2.93    0.00    9.44   68.68    0.00   18.95
               2.02    0.00    5.03   62.21    0.00   30.73
               2.30    0.00    6.99   69.24    0.00   21.47
               7.43    0.00    6.35   68.76    0.00   17.45
               6.63    0.00   15.24   61.14    0.00   16.99
               6.37    0.00   12.22   66.69    0.00   14.73
               7.44    0.00   13.48   64.41    0.00   14.67
               1.59    0.00    2.16   81.48    0.00   14.76
               8.89    0.00   13.72   64.28    0.00   13.11
               4.74    0.00    5.52   77.09    0.00   12.65
               5.57    0.00    9.39   72.62    0.00   12.42
               9.20    0.00   13.25   63.39    0.00   14.16
               7.95    0.00   12.44   65.51    0.00   14.11
              11.55    0.00   14.41   60.93    0.00   13.11
               9.60    0.00   15.77   62.18    0.00   12.44
               3.92    0.00   15.74   59.88    0.00   20.46
               5.34    0.00   19.68   55.40    0.00   19.58
               7.11    0.00   19.83   55.26    0.00   17.81
               6.17    0.00   16.61   57.38    0.00   19.84
               6.29    0.00   16.96   56.82    0.00   19.93
               6.26    0.00   17.32   55.47    0.00   20.95
               6.20    0.00    8.00   56.80    0.00   29.00
               9.91    0.00    7.30   50.51    0.00   32.28
              18.88    0.00    6.58   46.38    0.00   28.16
               7.03    0.00    0.15    0.43    0.00   92.39
    
    Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
    mmcblk2          76.61       450.41      1382.78     810772    2489124
    mmcblk2         118.21       657.84      1485.70    1204804    2721000
    mmcblk2          71.49       515.17      1415.50     955424    2625136
    mmcblk2          35.76       296.81      1296.73     568028    2481664
    mmcblk2         201.44       977.12       848.80    1840180    1598524
    mmcblk2          29.22        16.47       110.05      28892     193032
    mmcblk2          97.93       293.55       159.87     535056     291392
    mmcblk2          78.06       206.14       127.74     369048     228684
    mmcblk2          65.40       167.94       148.04     324444     286004
    mmcblk2         135.49       394.42       180.17     685148     312972
    mmcblk2          75.55       201.50       153.93     355436     271520
    mmcblk2         143.00       401.61       227.92     749180     425180
    mmcblk2         156.31       396.85       262.57     713496     472064
    mmcblk2         139.27       240.70       347.53     435308     628516
    mmcblk2         161.35       251.15       506.99     449260     906896
    mmcblk2         239.78       528.38       476.98     949888     857484
    mmcblk2         172.31       352.63       400.22     642808     729560
    mmcblk2         178.92       468.90       311.74     844492     561436
    mmcblk2         340.91       799.06       710.93    1439004    1280280
    mmcblk2         277.69       683.66       547.90    1232240     987552
    mmcblk2         321.37       796.36       631.85    1443872    1145604
    mmcblk2          77.21       181.19       156.36     327988     283040
    mmcblk2         317.58       788.05       607.13    1407312    1084220
    mmcblk2         157.16       407.68       282.06     744680     515216
    mmcblk2         198.91       439.60       443.84     787068     794652
    mmcblk2         337.17       818.63       667.23    1474116    1201480
    mmcblk2         332.78       796.49       659.56    1431248    1185196
    mmcblk2         373.29       972.52       664.27    1750564    1195704
    mmcblk2         335.74       778.88       707.79    1405296    1277036
    mmcblk2         326.77       801.76       669.36    1445520    1206824
    mmcblk2         357.16      1028.33       668.17    1845528    1199148
    mmcblk2         328.49       891.48       669.25    1604684    1204672
    mmcblk2         325.89       861.09       661.31    1553152    1192808
    mmcblk2         358.29       981.11       661.84    1776640    1198484
    mmcblk2         420.42      1245.85       659.41    2232780    1181772
    mmcblk2         470.04      1186.00       723.31    2133452    1301144
    mmcblk2         518.43      1405.45       696.22    2534760    1255640
    mmcblk2         477.34      1259.47       666.39    2264684    1198256
    mmcblk2          12.11        69.58        49.24     125248      88636

     

  13. 13 hours ago, sakibnaz said:

    is there any Open Hardware project which I can consider as base of my study. All the available SBC's are open source

     

    These 'open source' claims are BS almost everywhere. You need to pick one of the few Open Source Hardware protagonists, for example Olimex: https://www.olimex.com/Products/SOM204/ (RK3328 in the pipeline so if you're able to wait until 2019 maybe that's something for you)

     

    Apart from this I can not follow since RK3328, RK3329, RK3229 and RK3399 are different beasts (only two of them receiving good 'open source' support by Rockchip and RK3329 not even existing)

     

    Also worth to mention: Assumptions (like USB3 == great performance) should be questioned/checked.

  14. 6 hours ago, ag123 said:

     

    Oh, there's something we also need to take care of with upgrades: the existing 128MB swap file on SD card present in /etc/fstab:

                  total        used        free      shared  buff/cache   available
    Mem:           494M         66M        269M        2.7M        158M        415M
    Swap:          375M          0B        375M
    
    NAME       ALGORITHM DISKSIZE  DATA COMPR TOTAL STREAMS MOUNTPOINT
    /dev/zram0                50M 11.1M  2.9M  3.3M       4 /var/log
    /dev/zram1 lz4          61.8M    4K   63B    4K       4 [SWAP]
    /dev/zram2 lz4          61.8M    4K   63B    4K       4 [SWAP]
    /dev/zram3 lz4          61.8M    4K   63B    4K       4 [SWAP]
    /dev/zram4 lz4          61.8M    4K   63B    4K       4 [SWAP]

    With vm.swappiness=100 now it might be possible that the system decides to start to swap to SD card even if swap priority is pretty low. @Igor what do you think? Checking size of swap file and if it's 'our' 128MB file then removing fstab entry and swap file on upgrade?

  15. 14 hours ago, tkaiser said:

    While zram is a nice way to make more use of the physically available DRAM the whole approach still sucks since we would need to take care also about our attempts to store browser profiles and caches in RAM (uncompressed -- what a waste)

     

    Prepared a potential method to workaround that: https://github.com/armbian/build/commit/098a391996a4cd56d6e493d94decc85a53254ff1

     

    Needs a lot of testing of course...

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