On 06/13/2011 01:55 PM, Stefan Kaltenbrunner wrote: [...]
> all those tests are done with pgbench running on the same box - which > has a noticable impact on the results because pgbench is using ~1 core > per 8 cores of the backend tested in cpu resoures - though I don't think > it causes any changes in the results that would show the performance > behaviour in a different light. actuall testing against sysbench with the very same workload shows the following performance behaviour: with 40 threads(aka the peak performance point): pgbench: 223308 tps sysbench: 311584 tps with 160 threads (backend contention dominated): pgbench: 57075 sysbench: 43437 so it seems that sysbench is actually significantly less overhead than pgbench and the lower throughput at the higher conncurency seems to be cause by sysbench being able to stress the backend even more than pgbench can. for those curious - the profile for pgbench looks like: samples % symbol name 29378 41.9087 doCustom 17502 24.9672 threadRun 7629 10.8830 pg_strcasecmp 5871 8.3752 compareVariables 2568 3.6633 getVariable 2167 3.0913 putVariable 2065 2.9458 replaceVariable 1971 2.8117 parseVariable 534 0.7618 xstrdup 278 0.3966 xrealloc 137 0.1954 xmalloc Stefan -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
