64-bit lnx vs win client, Prime95.exe under Wine?

[xorbe]

With i7 and 8 threads, seems like the Windows client is ~20% faster on P-1.

So, does Prime95.exe work under Wine, and would it be multi-threaded? And would it actually help, or is this a scheduler thing or a runtime code path selection thing?

[lfm]

Originally Posted by xorbe

With i7 and 8 threads, seems like the Windows client is ~20% faster on P-1.

So, does Prime95.exe work under Wine, and would it be multi-threaded? And would it actually help, or is this a scheduler thing or a runtime code path selection thing?

are they the same version of gimps? both version 25.9 build 3 or what?

[xorbe]

I need to reboot back into Windows for A-B-A to make sure it's not just slowing down, but yeah I tried 32- and 64- bit both v25.8 and v25.9

[xorbe]

Yeah booted back to Windows, win64 client is at least 33% faster. It seems to be 50-60% vs 82-85% cpu utilization, Linux vs Vista, that is. 1630s vs 1220s.

Due to utilization being low in Linux, seems like that's a scheduler thing, or a software synchronization thing.

I can at least try a different scheduler in Linux, but later though.

[Kevin]

cat /proc/cpuinfo

Make sure the cpu mhz entry is what it should be. Intel's SpeedStep doesn't work well on Linux sometimes. On my new Linux computer, my processor was underclocked by about 20% until I turned off SpeedStep in the BIOS.

[jrk]

Originally Posted by Kevin

cat /proc/cpuinfo

Make sure the cpu mhz entry is what it should be. Intel's SpeedStep doesn't work well on Linux sometimes. On my new Linux computer, my processor was underclocked by about 20% until I turned off SpeedStep in the BIOS.

It was working, but it is set up to ignore low priority tasks when determining whether to start performance mode. So if the only thing running is mprime, which runs at idle priority, the CPU will stay in power saving mode.

xorbe needs to check that he doesn't have CPU scaling enabled, and either disable it or set mprime to run at a higher priority.

[geoff]

Originally Posted by jrk

It was working, but it is set up to ignore low priority tasks when determining whether to start performance mode. So if the only thing running is mprime, which runs at idle priority, the CPU will stay in power saving mode.

xorbe needs to check that he doesn't have CPU scaling enabled, and either disable it or set mprime to run at a higher priority.

Does anyone know the minimum priority level a process can run at without triggering CPU frequency scaling on Linux? Is there a standard or does it vary between each Linux distribution?

[jrk]

Originally Posted by geoff

Does anyone know the minimum priority level a process can run at without triggering CPU frequency scaling on Linux? Is there a standard or does it vary between each Linux distribution?

I believe it is the lowest priority only that is ignored, but I am not 100% sure. I don't have the cpu governor enabled here to check.

But in any case if you want the governor to not ignore the nice'd tasks, you can do:

echo 0 > /sys/devices/system/cpu/cpu0/cpufreq/ondemand/ignore_nice_load

For each cpu0, cpu1, etc however many cpus you have.

[xorbe]

BIOS does not have auto-anything enabled, and it is pegged at 3657 according to /proc/cpuinfo. I don't even have the cpufreq module loaded. I've even reniced the threads to priority 0. The % utilization simply trails Win64 -- either Linux scheduler is bouncing the threads around, or not scheduling well, or the Linux client doesn't synchronize as well. (Win64 client achieves 82-85% utilization.) I could not figure out how to reboot with a different CPU scheduler -- maybe that's only for the IO scheduler.

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND 
18493 xorbe     20   0  539m 396m 2788 S   62  6.6   4:46.94 mprime64-258
18492 xorbe     20   0  539m 396m 2788 S   62  6.6   4:57.95 mprime64-258
18095 xorbe     20   0  539m 396m 2788 S   58  6.6   4:56.52 mprime64-258
18489 xorbe     20   0  539m 396m 2788 S   58  6.6   5:04.49 mprime64-258
18491 xorbe     20   0  539m 396m 2788 S   58  6.6   5:06.22 mprime64-258
18490 xorbe     20   0  539m 396m 2788 R   55  6.6   5:08.20 mprime64-258
18488 xorbe     20   0  539m 396m 2788 S   52  6.6   4:18.76 mprime64-258
18494 xorbe     20   0  539m 396m 2788 S   52  6.6   4:35.75 mprime64-258

[fivemack]

Does the CPU use go up if you do

taskset -p 01 18493
taskset -p 02 18492
taskset -p 04 18095
taskset -p 08 18489
taskset -p 10 18491
taskset -p 20 18490
taskset -p 40 18488
taskset -p 80 18494

to lock each task onto its own execution thread?

[jrk]

Try turning off the group scheduler (CONFIG_GROUP_SCHED). That will require a kernel recompile.