On Mon, Jan 26, 2015 at 8:04 PM, Andres Freund <and...@2ndquadrant.com> wrote: > On 2015-01-26 19:58:25 -0500, Bruce Momjian wrote: >> On Tue, Jan 27, 2015 at 01:43:41AM +0100, Andres Freund wrote: >> > master + 32align.patch: >> > -c max_connections=400 >> > tps = 183791.872359 (high run vs. run variability) >> > -c max_connections=401 >> > tps = 185494.98244 (high run vs. run variability) >> > >> > master + 64align.patch: >> > -c max_connections=400 >> > tps = 489257.195570 >> > -c max_connections=401 >> > tps = 490496.520632 >> > >> > Pretty much as expected, rigth? >> >> Yes, I am convinced. Let's work on a patch now. > > Since I can reproduce some minor (1-3%) performance *regressions* at low > client counts when aligning every shmem allocation, I'm inclined to just > add special case code to BufferShmemSize()/InitBufferPool() to align > descriptors to PG_CACHE_LINE_SIZE. That's really unlikely to regress > anythign as it basically can't be a bad idea to align buffer > descriptors. > > Contrary opinions? Robert?
I'm totally OK with further aligning just that one allocation. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers