On 2019/8/6 22:17, Phil Auld wrote: > On Tue, Aug 06, 2019 at 09:54:01PM +0800 Aaron Lu wrote: >> On Mon, Aug 05, 2019 at 04:09:15PM -0400, Phil Auld wrote: >>> Hi, >>> >>> On Fri, Aug 02, 2019 at 11:37:15AM -0400 Julien Desfossez wrote: >>>> We tested both Aaron's and Tim's patches and here are our results. >>>> >>>> Test setup: >>>> - 2 1-thread sysbench, one running the cpu benchmark, the other one the >>>> mem benchmark >>>> - both started at the same time >>>> - both are pinned on the same core (2 hardware threads) >>>> - 10 30-seconds runs >>>> - test script: https://paste.debian.net/plainh/834cf45c >>>> - only showing the CPU events/sec (higher is better) >>>> - tested 4 tag configurations: >>>> - no tag >>>> - sysbench mem untagged, sysbench cpu tagged >>>> - sysbench mem tagged, sysbench cpu untagged >>>> - both tagged with a different tag >>>> - "Alone" is the sysbench CPU running alone on the core, no tag >>>> - "nosmt" is both sysbench pinned on the same hardware thread, no tag >>>> - "Tim's full patchset + sched" is an experiment with Tim's patchset >>>> combined with Aaron's "hack patch" to get rid of the remaining deep >>>> idle cases >>>> - In all test cases, both tasks can run simultaneously (which was not >>>> the case without those patches), but the standard deviation is a >>>> pretty good indicator of the fairness/consistency. >>>> >>>> No tag >>>> ------ >>>> Test Average Stdev >>>> Alone 1306.90 0.94 >>>> nosmt 649.95 1.44 >>>> Aaron's full patchset: 828.15 32.45 >>>> Aaron's first 2 patches: 832.12 36.53 >>>> Aaron's 3rd patch alone: 864.21 3.68 >>>> Tim's full patchset: 852.50 4.11 >>>> Tim's full patchset + sched: 852.59 8.25 >>>> >>>> Sysbench mem untagged, sysbench cpu tagged >>>> ------------------------------------------ >>>> Test Average Stdev >>>> Alone 1306.90 0.94 >>>> nosmt 649.95 1.44 >>>> Aaron's full patchset: 586.06 1.77 >>>> Aaron's first 2 patches: 630.08 47.30 >>>> Aaron's 3rd patch alone: 1086.65 246.54 >>>> Tim's full patchset: 852.50 4.11 >>>> Tim's full patchset + sched: 390.49 15.76 >>>> >>>> Sysbench mem tagged, sysbench cpu untagged >>>> ------------------------------------------ >>>> Test Average Stdev >>>> Alone 1306.90 0.94 >>>> nosmt 649.95 1.44 >>>> Aaron's full patchset: 583.77 3.52 >>>> Aaron's first 2 patches: 513.63 63.09 >>>> Aaron's 3rd patch alone: 1171.23 3.35 >>>> Tim's full patchset: 564.04 58.05 >>>> Tim's full patchset + sched: 1026.16 49.43 >>>> >>>> Both sysbench tagged >>>> -------------------- >>>> Test Average Stdev >>>> Alone 1306.90 0.94 >>>> nosmt 649.95 1.44 >>>> Aaron's full patchset: 582.15 3.75 >>>> Aaron's first 2 patches: 561.07 91.61 >>>> Aaron's 3rd patch alone: 638.49 231.06 >>>> Tim's full patchset: 679.43 70.07 >>>> Tim's full patchset + sched: 664.34 210.14 >>>> >>> >>> Sorry if I'm missing something obvious here but with only 2 processes >>> of interest shouldn't one tagged and one untagged be about the same >>> as both tagged? >> >> It should. >> >>> In both cases the 2 sysbenches should not be running on the core at >>> the same time. >> >> Agree. >> >>> There will be times when oher non-related threads could share the core >>> with the untagged one. Is that enough to account for this difference? >> >> What difference do you mean? > > > I was looking at the above posted numbers. For example: > >>>> Sysbench mem untagged, sysbench cpu tagged >>>> Aaron's 3rd patch alone: 1086.65 246.54 > >>>> Sysbench mem tagged, sysbench cpu untagged >>>> Aaron's 3rd patch alone: 1171.23 3.35 > >>>> Both sysbench tagged >>>> Aaron's 3rd patch alone: 638.49 231.06 > > > Admittedly, there's some high variance on some of those numbers.
The high variance suggests the code having some fairness issues :-) For the test here, I didn't expect the 3rd patch being used alone since the fairness is solved by patch2 and patch3 together.
