On Wed, Dec 24, 2014 at 11:20 AM, Andres Freund <and...@2ndquadrant.com> wrote: > I just verified that I can still reproduce the problem: > > # aligned case (max_connections=401) > afreund@axle:~$ pgbench -P 1 -h /tmp/ -p5440 postgres -n -M prepared -c 96 -j > 96 -T 100 -S > progress: 1.0 s, 405170.2 tps, lat 0.195 ms stddev 0.928 > progress: 2.0 s, 467011.1 tps, lat 0.204 ms stddev 0.140 > progress: 3.0 s, 462832.1 tps, lat 0.205 ms stddev 0.154 > progress: 4.0 s, 471035.5 tps, lat 0.202 ms stddev 0.154 > progress: 5.0 s, 500329.0 tps, lat 0.190 ms stddev 0.132 > > BufferDescriptors is at 0x7f63610a6960 (which is 32byte aligned) > > # unaligned case (max_connections=400) > afreund@axle:~$ pgbench -P 1 -h /tmp/ -p5440 postgres -n -M prepared -c 96 -j > 96 -T 100 -S > progress: 1.0 s, 202271.1 tps, lat 0.448 ms stddev 1.232 > progress: 2.0 s, 223823.4 tps, lat 0.427 ms stddev 3.007 > progress: 3.0 s, 227584.5 tps, lat 0.414 ms stddev 4.760 > progress: 4.0 s, 221095.6 tps, lat 0.410 ms stddev 4.390 > progress: 5.0 s, 217430.6 tps, lat 0.454 ms stddev 7.913 > progress: 6.0 s, 210275.9 tps, lat 0.411 ms stddev 0.606 > BufferDescriptors is at 0x7f1718aeb980 (which is 64byte aligned)
So, should we increase ALIGNOF_BUFFER from 32 to 64? Seems like that's what these results are telling us. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
