Luke Lonergan wrote:
Can you try this with just "-O3" versus "-O2"?
Thanks to Daniel for doing these tests. I happen to have done the same tests about 3/4 years ago, and concluded that gcc flags did *not* influence performance. Moved by curiosity, I revamped those tests now on a test machine (single P4 @ 3.2 Ghz, with 2Mb cache and 512 Mb Ram). Here are the results: http://www.streppone.it/cosimo/work/pg/gcc.png In short: tests executed with postgresql 8.2.0, gcc version 3.4.3 20041212 (Red Hat 3.4.3-9.EL4), tps figures computed as average of 9 pgbench runs (don't ask why 9... :-), with exactly the same commands given by Daniel: "-O0" ~ 957 tps "-O1 -mcpu=pentium4 -mtune=pentium4" ~ 1186 tps "-O2 -mcpu=pentium4 -mtune=pentium4" ~ 1229 tps "-O3 -mcpu=pentium4 -mtune=pentium4" ~ 1257 tps "-O6 -mcpu=pentium4 -mtune=pentium4" ~ 1254 tps I'm curious now to get the same tests run with a custom-cflags-compiled glibc. -- Cosimo
