[Gc] gcc prefetch accidentally disabled
hans.boehm at hp.com
Thu Jul 20 17:08:05 PDT 2006
Thanks. That's interesting.
I have no idea about the 10% difference. Performance is very sensitive
to the mark loop, and I have seen significant differences there between
compilers. On X86, I would guess it's a difference in the register
allocator and the generated spill code. But that's only a guess.
> -----Original Message-----
> From: gc-bounces at napali.hpl.hp.com
> [mailto:gc-bounces at napali.hpl.hp.com] On Behalf Of Peter Wang
> Sent: Wednesday, July 19, 2006 11:54 PM
> To: Boehm, Hans
> Cc: gc at napali.hpl.hp.com
> Subject: Re: [Gc] gcc prefetch accidentally disabled
> On 2006-07-19, Hans Boehm <Hans.Boehm at hp.com> wrote:
> > Thanks. I checked the patch into 7.0 CVS. If there is a
> 6.9 release
> > I'll include it there, too.
> > Any idea whether there is a significant performance impact?
> It seems
> > to vary greatly across platforms.
> > Hans
> It seems to make the Mercury compiler ~4% faster (in a
> particular configuration). This is with gcc 3.3.5.
> BTW, when the collector is compiled with gcc 3.4.4 it seems
> to be around 10% slower (nothing to do with the prefetching
> change, and the rest of Mercury compiled with gcc 3.4.4).
> Have you seen that before?
> Gc mailing list
> Gc at linux.hpl.hp.com
More information about the Gc