On Thu, Oct 4, 2018 at 9:50 AM Adrien Nayrat <adrien.nay...@anayrat.info> wrote: > > On 10/3/18 11:29 PM, Daniel Wood wrote: > > If running benchmarks or you are a customer which is currently impacted by > > GetSnapshotData() on high end multisocket systems be wary of Skylake-S. > > > > > > Performance differences of nearly 2X can be seen on select only pgbench due > > to > > nothing else but unlucky choices for max_connections. Scale 1000, 192 local > > clients on a 2 socket 48 core Skylake-S(Xeon Platinum 8175M @ 2.50-GHz) > > system. > > pgbench -S > > Could it be related to : > https://www.postgresql.org/message-id/D2B9F2A20670C84685EF7D183F2949E2373E66%40gigant.nidsa.net > ?
Unlikely. I understood from Daniel's email that profiling shows a different hot-spot. In the cited .NET issue the problem was mostly due to issuing PAUSE in a loop without attempting to grab the lock. In PostgreSQL it's called only once per retry attempt. Regards, Ants Aasma -- PostgreSQL Senior Consultant www.cybertec-postgresql.com Austria (HQ), Wiener Neustadt | Switzerland, Zürich | Estonia, Tallinn | Uruguay, Montevideo Facebook: www.fb.com/cybertec.postgresql Twitter: www.twitter.com/PostgresSupport
