Re: brk() function and performance

Yow.  What are those Solaris engineers doing over there?

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Andrew Sullivan wrote:
> On Thu, Jul 11, 2002 at 12:30:12PM -0400, Andrew Sullivan wrote:
> > Hi,
> >
> > We're running PostgreSQL 7.1.3 (I know, I know) on Solaris 7 on two
> > Sun E4500s with 8 CPUs and 16 Gig of RAM.
> >
> > We have noticed that one of the machines is considerably slower than
> > the other.  We have traced the problem to the brk() funciton call.
>
> My Sun-loving colleague, Sorin Iszlai, wondered why this problem was
> cropping up, and remembered the qsort() debacle.  So he did some
> tests.  Guess what?  Here's what he found:
>
> > I ran some tests with the realloc() function from the standard lib;
> > If the application calls realloc() 4096 times the results are:
>
> > - if linked with bsdmalloc, realloc() calls brk() 17 times only:
> > syscall      seconds   calls
> > brk              .40      17
>
> > - and without bsdmalloc :
> > syscall      seconds   calls
> > brk             1.36   24527
>
> At this rate, I'm beginning to get the feeling that maybe getting
> FreeBSD to work well on 64 bit Sun machines is the most important
> project we could undertake ;-)
>
> Anyway, I'm going to do some tests with this, but in the meantime, if
> anyone has any views on the subject, insights, or experience, it'd be
> much appreciated.
>
> Thanks.
>
> A
>
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