Messages in this thread | | | From | Luca Zini <> | Subject | Re: scheduler vs hardware? (was Re: another i7 (linux) bug?) | Date | Fri, 22 Jan 2010 12:22:28 +0100 |
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First of all sorry for misunderstanding with Alex Chiang, I was trying to collect some data from other i7 mobile users to try to isolate the problem before posting.
I tried different things: I disabled speedstep from the bios and the results where more sensible (higher priority lower execution time). The same thing happens if I disable throttling by software selecting "aggressive powersave" settings.
So I suppose that is something related directly or indirectly to frequency scaling or turbo boost (unfortunately I have no bios option to disable only turbo boost) Here are the results of the same test of Peter Zijlstra
time sudo nice -n 19 lame -b 256 -V0 -h youcantdothat.wav 2&> /dev/null
real 0m1.105s user 0m1.090s sys 0m0.010s
time sudo nice -n 0 lame -b 256 -V0 -h youcantdothat.wav 2&> /dev/null
real 0m1.108s user 0m1.100s sys 0m0.010s
time sudo nice -n -20 lame -b 256 -V0 -h youcantdothat.wav 2&> /dev/null
real 0m1.354s user 0m1.330s sys 0m0.000s
They are almost the same results that I obtained before. Looking at top there are no other process that is using the cpu (main are Xorg and kopete).
I tested this on 2.6.31-17-server (ubuntu 9.10) 2.6.31-17-generic (ubuntu 9.10) and the default kernel of fedora 12 (live cd). As soon as possible I'll try 33-rc5 as requested by Mike Galbraith (now I can't shut down the computer).
Ok, a last minute update! I slightly modified i7z to save a log to disk. If i7z output are reliable I suppose that it can show is the problem: with nice set to 19 a processor 3 reach the maximum speed, with nice set to -20 its maximum value is 300-400 mhz under the maximum value. (I attach the two logs named as the nice level used obtained running lame on a bigger file) Please note that logs may have some value read before and/or after the start/end of the running process (lame).
The next update will be the results with 33-rc5 kernel.
Luca Processor 0: 1062.13 (7.99x) 1 99.7 0 98.5 Processor 1: 1246.75 (9.37x) 1 99.8 0 99 Processor 2: 1113.41 (8.37x) 1 99.8 0 98.4 Processor 3: 1477.30 (11.11x) 4.67 95.7 0 85.7 Processor 0: 1109.70 (8.34x) 1 99.7 2.93 95.8 Processor 1: 2316.51 (17.42x) 5.5 92 0 91.7 Processor 2: 1114.96 (8.38x) 1 99.8 14.9 83.7 Processor 3: 1225.48 (9.21x) 9.95 92.4 1.33 67.6 Processor 0: 1877.15 (14.11x) 1 99.8 29.6 69.9 Processor 1: 1914.75 (14.40x) 1 99.2 1 98.1 Processor 2: 1955.22 (14.70x) 1 99.8 0 99.4 Processor 3: 2402.49 (18.06x) 38.8 41.6 0 0 Processor 0: 2114.28 (15.90x) 12 84.1 0 35.4 Processor 1: 1528.62 (11.49x) 1 99.8 25.4 73.2 Processor 2: 1582.10 (11.90x) 1 99.9 74.2 25.2 Processor 3: 2359.66 (17.74x) 14.6 78.3 18.6 56 Processor 0: 2242.78 (16.86x) 16.3 77.1 0 0 Processor 1: 1591.62 (11.97x) 1 99.9 87.9 10.9 Processor 2: 1885.84 (14.18x) 1 100 99.2 1 Processor 3: 2035.81 (15.31x) 1.77 97.7 15 75.4 Processor 0: 2280.59 (17.15x) 18.3 73.8 1 70.4 Processor 1: 1906.72 (14.34x) 1 99.7 26.9 72 Processor 2: 1778.56 (13.37x) 1 99.9 70.9 28.6 Processor 3: 1077.58 (8.10x) 8.56 94.2 3.66 4.79 Processor 0: 2009.19 (15.11x) 7.07 91.1 1 88.3 Processor 1: 1708.96 (12.85x) 1 99.8 37.3 61.5 Processor 2: 1673.01 (12.58x) 1 99.9 13.4 85.9 Processor 3: 1421.09 (10.68x) 12.1 89.2 1 21.8 Processor 0: 935.30 (7.03x) 1 99.8 0 73.4 Processor 1: 938.46 (7.06x) 1 99.9 0 98.3 Processor 2: 932.33 (7.01x) 1 99.9 0 97.7 Processor 3: 1017.69 (7.65x) 6.09 96.1 0 92.1 Processor 0: 1040.73 (7.83x) 1 99.8 0 99.1 Processor 1: 1062.37 (7.99x) 1 99.7 0 96.1 Processor 2: 1047.94 (7.88x) 1 99.8 1 97.7 Processor 3: 1941.75 (14.60x) 11.1 86.5 2.98 81.5 Processor 0: 1940.64 (14.59x) 1 99.5 0 72.7 Processor 1: 1600.11 (12.03x) 1 99.8 11.5 86 Processor 2: 2141.58 (16.10x) 1 100 99.6 1 Processor 3: 2760.11 (20.75x) 83.2 0 4.33 11.6 Processor 0: 2331.59 (17.53x) 1 99.4 5.98 93 Processor 1: 2287.80 (17.20x) 1 99.8 0 97.6 Processor 2: 2122.39 (15.96x) 1 100 88.5 11.1 Processor 3: 2774.36 (20.86x) 99.9 0 0 0 Processor 0: 2322.64 (17.46x) 1 99.5 1 98.6 Processor 1: 2275.29 (17.11x) 1 99.8 1 97.9 Processor 2: 2268.43 (17.06x) 1 99.8 0 99.5 Processor 3: 2779.36 (20.90x) 99.9 0 0 0 Processor 0: 2277.58 (17.12x) 1 99.8 0 99.6 Processor 1: 2372.66 (17.84x) 1 99.5 0 99.2 Processor 2: 2346.90 (17.65x) 1 99.8 0 99.5 Processor 3: 2783.34 (20.93x) 99.9 0 0 0
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