Paul Mackerras <pau...@ozlabs.org> writes: > On Fri, Oct 27, 2017 at 10:57:13AM +0530, Aneesh Kumar K.V wrote: >> >> >> On 10/27/2017 10:04 AM, Paul Mackerras wrote: >> >How do we interpret these numbers? Are they times, or speed? Is >> >larger better or worse? >> >> Sorry for not including the details. They are time in seconds. Test case is >> a modified mmap_bench included in powerpc/selftest. >> >> > >> >Can you give us the mean and standard deviation for each set of 5 >> >please? >> > >> >> powernv without patch >> median= 51.432255 >> stdev = 0.370835 >> >> with patch >> median = 50.739922 >> stdev = 0.06419662 >> >> pseries without patch >> median = 116.617884 >> stdev = 3.04531023 >> >> with patch no hcall >> median = 119.42494 >> stdev = 0.85874552 >> >> with patch and hcall >> median = 117.735808 >> stdev = 2.7624151 > > So on powernv, the patch set *improves* performance by about 1.3% > (almost 2 standard deviations). Do we know why that is?
I haven't looked at that closely. I was considering it within runtime variance (no impact with patch series). I will get perf record collected and will see if that points to any details. > > On pseries, performance is about 2.4% worse without new hcalls, but > that is less than 1 standard deviation. With new hcalls, performance > is 0.95% worse, only a third of a standard deviation. I think we need > to do more measurements to try to get a more accurate picture here. > > Were the pseries numbers done on KVM or PowerVM? Could you do a set > of measurements on the other one too please? (I assume the numbers > with the new hcall were done on KVM, and can't be done on PowerVM.) > The above pseries numbers were collected on KVM. PowerVM numbers on a different machine: Without patch 31.194165 31.372913 31.253494 31.416198 31.199180 MEDIAN = 31.253494 STDEV = 0.1018900 With patch series 31.538281 31.385996 31.492737 31.452514 31.259461 MEDIAN = 31.452514 STDEV = 0.108511 -aneesh