Re: [Testperf-general] Re: First set of OSDL Shared Memscalability results, some wierdness ...

On Fri, Oct 15, 2004 at 05:44:34PM -0400, Tom Lane wrote:
> Mark Wong <markw(at)osdl(dot)org> writes:
> > On Fri, Oct 15, 2004 at 05:27:29PM -0400, Tom Lane wrote:
> >> Hmm, in that case the cost deserves some further investigation. Can we
> >> find out just what that routine does and where it's being called from?
>
> > There's a call-graph feature with oprofile as of version 0.8 with
> > the opstack tool, but I'm having a terrible time figuring out why the
> > output isn't doing the graphing part. Otherwise, I'd have that
> > available already...
>
> I was wondering if this might be associated with do_sigaction.
> do_sigaction is only 0.23 percent of the runtime according to the
> oprofile results:
> http://khack.osdl.org/stp/298124/oprofile/DBT_2_Profile-all.oprofile.txt
> but the profile results for the same run:
> http://khack.osdl.org/stp/298124/profile/DBT_2_Profile-tick.sort
> show do_sigaction very high and recalc_sigpending_tsk nowhere at all.
> Something funny there.
>

I have always attributed those kind of differences based on how
readprofile and oprofile collect their data. Granted I don't exactly
understand it. Anyone familiar with the two differences?

Mark