On 2015-06-10 09:18:56 -0400, Jan Wieck wrote: > On a machine with 8 sockets, 64 cores, Hyperthreaded 128 threads total, a > pgbench -S peaks with 50-60 clients around 85,000 TPS. The throughput then > takes a very sharp dive and reaches around 20,000 TPS at 120 clients. It > never recovers from there.
85k? Phew, that's pretty bad. What exact type of CPU is this? Which pgbench scale? Did you use -M prepared? Could you share a call graph perf profile? > The attached patch demonstrates that less aggressive spinning and > (much) more often delaying improves the performance "on this type of > machine". The 8 socket machine in question scales to over 350,000 TPS. Even that seems quite low. I've gotten over 500k TPS on a four socket x86 machine, and about 700k on a 8 socket x86 machine. Maybe we need to adjust the amount of spinning, but to me such drastic differences are a hint that we should tackle the actual contention point. Often a spinlock for something regularly heavily contended can be worse than a queued lock. Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
