On Thu, Sep 21, 2017 at 7:25 AM, Robert Haas <robertmh...@gmail.com> wrote: > On Wed, Sep 20, 2017 at 9:46 PM, Mithun Cy <mithun...@enterprisedb.com> wrote: >> I think there is some confusion above results is for pgbench simple update >> (-N) tests where cached snapshot gets invalidated, I have run this to check >> if there is any regression due to frequent cache invalidation and did not >> find any. The target test for the above patch is read-only case [1] where we >> can see the performance improvement as high as 39% (@256 threads) on >> Cthulhu(a 8 socket numa machine with 64 CPU cores). At 64 threads ( = CPU >> cores) we have 5% improvement and at clients 128 = (2 * CPU cores = >> hyperthreads) we have 17% improvement. >> >> Clients BASE CODE With patch %Imp >> >> 64 452475.929144 476195.952736 5.2422730281 >> >> 128 556207.727932 653256.029012 17.4482115595 >> >> 256 494336.282804 691614.000463 39.9075941867 > > Oh, you're right. I was confused. > > But now I'm confused about something else: if you're seeing a clear > gain at higher-client counts, why is Jesper Pederson not seeing the > same thing? Do you have results for a 2-socket machine? Maybe this > only helps with >2 sockets.
My current tests show on scylla (2 socket machine with 28 CPU core) I do not see any improvement at all as similar to Jesper. But same tests on power2 (4 sockets) and Cthulhu(8 socket machine) we can see improvements. -- Thanks and Regards Mithun C Y EnterpriseDB: http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers