po 14. 12. 2020 v 17:25 odesÃlatel Tom Lane <t...@sss.pgh.pa.us> napsal:
> Pavel Stehule <pavel.steh...@gmail.com> writes: > > I checked a performance and it looks so access to record's field is > faster, > > but an access to arrays field is significantly slower > > Hmm, I'd drawn the opposite conclusion in my own testing ... > > > for i in 1..5000 > > loop > > if a[i] > a[i+1] then > > aux := a[i]; > > a[i] := a[i+1]; a[i+1] := aux; > > rep := true; > > end if; > > end loop; > > ... but I now see that I'd not checked cases like "a[i] := a[j]". > exec_check_rw_parameter() is being too conservative about whether > it can optimize a case like that. The attached incremental patch > fixes it. > > > I tested pi calculation > > ... > > And the performance is 10% slower than on master > > Can't reproduce that here. For the record, I get the following > timings (medians of three runs) for your test cases: > > HEAD: > > sort: Time: 13974.709 ms (00:13.975) > pi_est_1(10000000): Time: 3537.482 ms (00:03.537) > pi_est_2(10000000): Time: 3546.557 ms (00:03.547) > > Patch v1: > > sort: Time: 47053.892 ms (00:47.054) > pi_est_1(10000000): Time: 3456.078 ms (00:03.456) > pi_est_2(10000000): Time: 3451.347 ms (00:03.451) > > + exec_check_rw_parameter fix: > > sort: Time: 12199.724 ms (00:12.200) > pi_est_1(10000000): Time: 3357.955 ms (00:03.358) > pi_est_2(10000000): Time: 3367.526 ms (00:03.368) > > I'm inclined to think that the differences in the pi calculation > timings are mostly chance effects; there's certainly no reason > why exec_check_rw_parameter should affect that test case at all. > performance patch helps lot of for sort - with patch it is faster 5-10% than master 10864 x 12122 ms I found probably reason why patched was slower I used CFLAGS="-fno-omit-frame-pointer -Wall -Wmissing-prototypes -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -g -O2 -Werror=switch" With these options the pi test was slower. When I used default, then there is no difference. So it can be very good feature, new code has same speed or it is faster Regards Pavel > regards, tom lane > >
