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Everything posted by wtarreau

  1. I tested a miner on it ("cpuminer" I think) to give numbers to a friend interested on the subject (he was impressed by the way). I didn't let it run for hours like this, but after several minutes it started to throttle down to 1 GHz then stabilized, but didn't stop (and keep in mind it's tightly enclosed in cardboard). It's certain that the modified DTB I'm using helps here with the higher temperature thresholds, but I'm suspecting you might have too weak a power supply or micro USB cable if it stopped. That's always the risk with DVFS : it consumes very little in idle but a lot under load. I
  2. That's quite different from what I'm seeing given that I had made my own enclosure out of cardboard with no air around it! Of course it heats but not that fast, despite the fact that I overclocked it. If the fan helps, it's probable that you're not having a good contact between the heatsink and the CPU. Verify that the heatsink is very parallel to the board, it's possible that it touches only by one angle.
  3. I must confess I absolutely don't remember what I used given that I always have everything I need for this. It's possible that I naturally placed a thermal pad in between. I don't remember having opened a thermal paste tube. Or maybe there was a pad with the heatsink. But definitely I didn't put raw aluminum on top of the CPU die without anything to make good contact in between.
  4. The 3 critical points (in degrees celcius) for the thermal throttling and shutdown. I didn't understand the difference between the first two ones, as the CPU starts to throttle when the first value is reached. The second *seems* to do nothing, the 3rd one is for the forced shutdown. I seem to remember that it starts throttling at 80. IIRC the original values were something like 80, 85 and 105. It definitely is very informative to do so. Do not forget that such boards will heat much more in summer than in winter (you can more or less shift the high te
  5. I'd say around 2 weeks. The default heatsink is enough if you're not running at 100% CPU full-time. For my use cases, it's mostly a network endpoint and I can run it at 1 Gbps without problems even with the board confined in a cardboard made enclosure. But if you run with all CPUs saturated, you'll reach around 5W that need to be dissipated one way or another. The default heatsink and the PCB are not large enough to dissipate 5W at a low temperature. I significantly raised the temperature thresholds (113, 115, 120) to prevent it from throttling too early. Note that these thresho
  6. @shaun27, you're pretty close to my measurements. I hadn't noticed your point about the shutdown, but I seem to remember noticing it didn't cut off. Maybe there's no way to completely shut the DC-DC and the CPUs are not stopped but looping in place. At the very least if that's the case, I think we could improve the situation by using a WFI instruction...
  7. I think you simply didn't read anything in this thread. The whole thread precisely is about Amlogic distributing to SBC vendors firmwares that *pretend* to run at these frequencies but do not. When it reports any frequency between 1.5 and 2 GHz, in fact it's still at 1.536 GHz. And the funny thing is that @tkaiser was precisely saying that it works since a lot of people don't verify and are absolutely convinced that the board runs at 2.02 GHz when it says so. So now thanks to you we have a perfect illustration of what he was saying ;-)
  8. I agree with FriendlyElec's USB cables, I've always found they were of pretty good quality. Same for the cables coming with the MiQi by the way. I've had good experiences with a few PSU providing 2.5A under 5.2V and featuring a micro-usb cable. Since there it's not possible to connect any other way, they have to provide a good enough cable and connector. But in my opinion these good ones are almost an exception to the general trend. Regarding the increase of consumption at 90 vs 50°C, I noticed this as well with the RK3288 boards from by first farm. It's in fact due to the lower ef
  9. @tkaiser , in fact there is a small category of users like me who do care about frequency because they do know their workload depends on frequency. My libslz compressor does (almost scales linearly). Crypto almost does when using native ARMv8 crypto extensions. My progressive locks code does as well. Compilation partially does. The problem I'm facing these days is that when I hit a performance wall with a board, I start to get a clear idea of what I'd like to try, and the minimum number I want for each metric to expect any improvement. For example I'm not interested in 32-bit memor
  10. Thomas, I think it's problematic that you only have a watt-meter including the PSU because the PSU's efficiency depends on the consumption (usually it's optimal around 50% load). Using a USB power meter would tell you the volts, amps and watts, and would even allow to detect under-power when it happens. I managed to get my board to shut down only once, it was powered by my laptop's USB3 port (that's what I do all the time but I'm probably close to the limit). It never happened on a 5V/2A PSU however. Since it was not yet very hot, I suspect that it's the power controller instead wh
  11. I totally agree, I've been pissed off by many boards on which it was not possible to have correct heat dissipation due to too large the distance between the CPU and the top of the enclosure. With the NEO/NEO2 now you can simply press the PCB (hence the CPU) against a thermal pad touching the enclosure and you're done. It's in fact one of the very rare board capable of spreading the heat outside of the enclosure and not to slowly heat its own environment. I wish other vendors would realize this as well. And yes, I know it's difficult and expensive to make dual-side BGA designs so that will
  12. I usually run "openssl speed rsa2048 -multi <#cores>" for this, the RSA code is carefully optimized to achieve a very high IPC on most CPUs and I always managed to achieve the highest power consumption with this. The only difficulty is that it doesn't last long (10s) so you have to measure quickly. Another benefit is that it often comes pre-installed on most systems.
  13. It's an over-simplification. The die technology and etching resolution matters a lot as well. And my NanoPI-M3 with 8xA53 at 1.4 GHz disagrees with you, just like my Odroid-C2 at 1.536 GHz which stays really cool to the touch at full speed. Some A53 run pretty fine at 2 GHz. You'd better say that A53 is mostly used in cheap devices and that cheap devices don't scale well above 1 GHz due to the cheap technologies involved, that would be more accurate.
  14. I've just tested on my MiQi and got about 2% higher performance at 1.8 GHz : type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes aes-128 cbc 80197.72k 87590.12k 91353.34k 92255.91k 92520.45k bf-cbc 52186.86k 59762.60k 62007.89k 62678.36k 62876.33k At 2.0 GHz I get this : type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes aes-128 cbc 88145.11k 97268.91k 101094.74k 102091.43k 102386.35k bf-cbc 57751.12k