Messages in this thread | | | From | Con Kolivas <> | Subject | Re: [PATCH] i386: Selectable Frequency of the Timer Interrupt | Date | Fri, 15 Jul 2005 14:08:36 +1000 |
| |
On Fri, 15 Jul 2005 09:25, Linus Torvalds wrote: > On Thu, 14 Jul 2005, Lee Revell wrote: > > On Thu, 2005-07-14 at 09:37 -0700, Linus Torvalds wrote: > > > I have to say, this whole thread has been pretty damn worthless in > > > general in my not-so-humble opinion. > > > > This thread has really gone OT, but to revisit the original issue for a > > bit, are you still unwilling to consider leaving the default HZ at 1000 > > for 2.6.13? > > Yes. I see absolutely no point to it until I actually hear people who have > actually tried some real load that doesn't work. Dammit, I want a real > user who says that he can noticeable see his DVD stuttering, not some > theory.
Disclaimer - This is not proof of a real world dvd stuttering, simply a benchmarked result. My code may be crap, but then the real apps out there may also be.
Results from interbench v0.21 (http://ck.kolivas.org/apps/interbench/interbench-0.21.tar.bz2)
2.6.13-rc1 on a pentium4 3.06
HZ=1000: --- Benchmarking Audio in the presence of loads --- Latency +/- SD (ms) Max Latency % Desired CPU % Deadlines Met None 0.012 +/- 0.00196 0.021 100 100 Video 1.28 +/- 0.509 2.01 100 100 X 0.289 +/- 0.578 2 100 100 Burn 0.014 +/- 0.002 0.023 100 100 Write 0.025 +/- 0.0349 0.49 100 100 Read 0.02 +/- 0.00383 0.052 100 100 Compile 0.023 +/- 0.00752 0.054 100 100 Memload 0.222 +/- 0.892 9.04 100 100
--- Benchmarking Video in the presence of loads --- Latency +/- SD (ms) Max Latency % Desired CPU % Deadlines Met None 0.012 +/- 0.00169 0.023 100 100 X 2.55 +/- 2.37 18.7 100 75.8 Burn 1.08 +/- 1.06 16.7 100 88.2 Write 0.224 +/- 0.215 16.7 100 97.8 Read 0.019 +/- 0.00354 0.059 100 100 Compile 4.55 +/- 4.53 17.6 100 57.5 Memload 1.3 +/- 1.34 51.5 100 88
HZ=250: --- Benchmarking Audio in the presence of loads --- Latency +/- SD (ms) Max Latency % Desired CPU % Deadlines Met None 0.011 +/- 0.00152 0.022 100 100 Video 0.157 +/- 0.398 3.62 100 100 X 1.3 +/- 1.82 4.01 100 100 Burn 0.014 +/- 0.00142 0.026 100 100 Write 0.022 +/- 0.0125 0.092 100 100 Read 0.021 +/- 0.00366 0.048 100 100 Compile 0.03 +/- 0.0469 0.559 100 100 Memload 0.144 +/- 0.681 8.05 100 100
--- Benchmarking Video in the presence of loads --- Latency +/- SD (ms) Max Latency % Desired CPU % Deadlines Met None 5 +/- 4.99 16.7 100 54 X 9.98 +/- 8.94 20.7 100 31.2 Burn 16.6 +/- 16.6 16.7 100 0.167 Write 4.11 +/- 4.08 16.7 100 60.8 Read 2.55 +/- 2.53 16.7 100 73.8 Compile 15.6 +/- 15.6 17.7 100 3.5 Memload 2.91 +/- 2.92 45.4 100 72.5
Audio did show slightly larger max latencies but nothing that would be of significance.
On video, maximum latencies are only slightly larger at HZ 250, all the desired cpu was achieved, but the average latency and number of missed deadlines was significantly higher.
Cheers, Con [unhandled content-type:application/pgp-signature] | |