Hi, Did someone try '-mfpmath=sse -msse3'? Would be interesting to know if -mfpmath=sse boost the performance. I guess, the difference in the generated code isn't that much between i686 and prescott. The bigger step is i386 to i686. '-mfpmath=sse -msse3' will also use the SSE unit, which the classic i686 doesn't have. CFLAGS=-O2 -march=prescott -mfpmath=sse -msse3 Best regards Sven. Daniel van Ham Colchete schrieb: > I just made another test with a second Gentoo machine: > > Pentium 4 3.0Ghz Prescott > GCC 4.1.1 > Glibc 2.4 > PostgreSQL 8.1.5 > Kernel 2.6.17 > > Same postgresql.conf as yesterday's. > > First test > ========== > GLIBC: -O2 -march=i686 > PostgreSQL: -O2 -march=i686 > Results: 974.638731 975.602142 975.882051 969.142503 992.914167 > 983.467131 983.231575 994.901330 970.375221 978.377467 > Average (error): 980 tps (13 tps) > > Second test > =========== > GLIBC: -O2 -march=i686 > PostgreSQL: -O2 -march=prescott > Results: 988.319643 976.152973 1006.482553 992.431322 983.090838 > 992.674065 989.216746 990.897615 987.129802 975.907955 > Average (error): 988 tps (15 tps) > > Third test > ========== > GLIBC: -O2 -march=prescott > PostgreSQL: -O2 -march=i686 > Results: 969.085400 966.187309 994.882325 968.715150 956.766771 > 970.151542 960.090571 967.680628 986.568462 991.756520 > Average (error): 973 tps (19 tps) > > Forth test > ========== > GLIBC: -O2 -march=prescott > PostgreSQL: -O2 -march=prescott > Results: 980.888371 978.128269 969.344669 978.021509 979.256603 > 993.236457 984.078399 981.654834 976.295925 969.796277 > Average (error): 979 tps (11 tps) > > The results showed no significant change. The conclusion of today's > test would be that there are no improvement at PostgreSQL when using > -march=prescott. > > I only see 3 diferences between yesterday's server and today's: the > kernel version (y: 2.6.18, t:2.6.17), the server uses an IDE harddrive > (yesterday was SATA), and the gcc version (3.4.6 -> 4.1.1). > > I don't know why yesterday we had improved and today we had not. > > Best > Daniel > > On 12/12/06, Daniel van Ham Colchete <daniel.colchete@xxxxxxxxx> wrote: >> I'm making some other tests here at another hardware (also Gentoo). I >> found out that PostgreSQL stops for a while if I change the -t >> parameter on bgbench from 600 to 1000 and I have ~150 tps instead of >> ~950tps.
