On Sun, Jun 11, 2006 at 09:58:33PM -0400, Tom Lane wrote: > Kris Kennaway <[EMAIL PROTECTED]> writes: > > On Sun, Jun 11, 2006 at 07:43:03PM -0400, Tom Lane wrote: > >> Let's see the evidence. > > > The calls to setproctitle() (it looks like 4 setproctitle syscalls per > > DB query) are causing contention on the Giant lock 25% of the time on > > a dual p4 + HTT. Disabling process title setting completely gives an > > 8% peak performance boost to the super-smack select benchmark. > > I think you misunderstood me: I asked for evidence, not interpretation. > What are you measuring, and with what tool, and what are the numbers? > On what benchmark case?
As I said, I'm using the super-smack select benchmark; presumably you are aware of it. > And what did you do to "disable process title setting completely"? Added this to ps_status.c: #undef PS_USE_SETPROCTITLE #undef PS_USE_PSTAT #undef PS_USE_PS_STRINGS #undef PS_USE_CHANGE_ARGV #undef PS_USE_CLOBBER_ARGV #define PS_USE_NONE Here are the queries/second data, before and after: x pg + pg-noproctitle +------------------------------------------------------------+ |x xx + | |x xx + + | |xx xxx + + + ++++ | | |AM| |____AM___|| +------------------------------------------------------------+ N Min Max Median Avg Stddev x 11 3399.29 3425.1 3413.93 3411.8418 9.4287675 + 10 3615.63 3699.32 3685.515 3679.344 24.894177 Difference at 95.0% confidence 267.502 +/- 16.871 7.8404% +/- 0.494483% (Student's t, pooled s = 18.4484) Kris
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