Hi Rafael, On 06/11/2013 02:24 AM, Rafael J. Wysocki wrote: > On Tuesday, June 11, 2013 12:57:26 AM Stratos Karafotis wrote: >> On 06/09/2013 11:58 PM, Rafael J. Wysocki wrote: >>> Well, this means that your changes may hurt performance if the load comes and >>> goes in spikes, which is not so good. The fact that they cause less energy to >>> be used at the same time kind of balance that, though. [After all, we're >>> talking about the ondemand governor which should be used if the user wants to >>> sacrifice some performance for energy savings.] >>> >>> It would be interesting to see if the picture changes for different time >>> intervals in your test program (e.g. loop duration that is not a multiple of >>> sampling_rate and sleep times different from 5000 us) to rule out any random >>> coincidences. >>> >>> Can you possibly prepare a graph showing both the execution time and energy >>> consumption for several different loop durations in your program (let's keep >>> the 5000 us sleep for now), including multiples of sampling_rate as well as >>> some other durations? >> >> Hi, >> >> I tested different loop durations with my program from 1,000us to 1,000,000us. >> The logic is almost the same with the previous test: >> >> 1) Use a 'for' loop to a period T (~ 1000-1000000us) >> 2) sleep for 5000us >> 3) Repeat steps 1-2, 50 times. >> 4) sleep for 1s >> 5) Repeat 1-4, 5 times. >> >> The results: >> https://docs.google.com/spreadsheet/ccc?key=0AnMfNYUV1k0ddE13ZUtYdGs2dUVRdG00bVRVT3JScWc&usp=sharing >> >> Sheet1 (ProcessX1) includes the results from the test program running >> as single copy. The second one (ProcessX4) includes the results from the test >> program running it in 4 copies in parallel (using a bash script that waits >> the end of execution). >> >> Graphs show the difference(%) in total execution time and total energy without >> and with the patch. >> Negative values mean that the test *with* the patch had better performance or >> used less energy. >> >> Test shows that below sampling rate (10000us in my config), ondemand with this >> patch behaves better (both in performance and consumption). >> Though, in this test, for loads with 10000us < duration <= 200000us ondemand >> behaves better without the patch. > > Thanks for these results! > > Well, I'd say that this doesn't look rosy any more, so the jury is still out. > > We need more testing with different workloads and on different hardware. I'll > try to arrange something to that end. Please let me share some more test results using aim9 benchmark suite: https://docs.google.com/spreadsheet/ccc?key=0AnMfNYUV1k0ddDdGdlJyUHpqT2xGY1lBOEt2UEVnNlE&usp=sharing Each test was running for 10sec. Total execution time with and without the patch was almost identical, which is expected since the tests in aim9 run for a specific period. The energy during the test run was increased by 0.43% with the patch. The performance was increased by 1.25% (average) with this patch. Thanks, Stratos -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
