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RE: Serious SPEC CPU 2006 FP performance regressions on IA32
- From: "Meissner, Michael" <michael dot meissner at amd dot com>
- To: "H. J. Lu" <hjl at lucon dot org>, "Menezes, Evandro" <evandro dot menezes at amd dot com>
- Cc: gcc at gcc dot gnu dot org, ubizjak at gmail dot com, "rajagopal, dwarak" <dwarak dot rajagopal at amd dot com>
- Date: Mon, 11 Dec 2006 14:34:00 -0500
- Subject: RE: Serious SPEC CPU 2006 FP performance regressions on IA32
> -----Original Message-----
> From: H. J. Lu [mailto:hjl@lucon.org]
> Sent: Monday, December 11, 2006 1:09 PM
> To: Menezes, Evandro
> Cc: gcc@gcc.gnu.org; ubizjak@gmail.com; rajagopal, dwarak; Meissner,
> Michael
> Subject: Re: Serious SPEC CPU 2006 FP performance regressions on IA32
>
> On Mon, Dec 11, 2006 at 11:35:27AM -0600, Menezes, Evandro wrote:
> > HJ,
> >
> > > > Gcc 4.3 revision 119497 has very poor SPEC CPU 2006 FP
performance
> > > > regressions on P4, Pentium M and Core Duo, comparing aganst
> > > > gcc 4.2 20060910. With -O2, the typical regressions look like
> > > >
> > > > Gcc 4.2 Gcc 4.3
> > > > 410.bwaves 9.89 9.14 -7.58342%
> > > > 416.gamess 7.17 7.16 -0.13947%
> > > > 433.milc 7.68 7.65 -0.390625%
> > > > 434.zeusmp 5.57 5.55 -0.359066%
> > > > 435.gromacs 3.99 4.02 0.75188%
> > > > 436.cactusADM 4.59 4.50 -1.96078%
> > > > 437.leslie3d 5.78 3.98 -31.1419%
> > > > 444.namd 6.25 6.18 -1.12%
> > > > 447.dealII 11.3 11.3 0%
> > > > 450.soplex 8.61 8.59 -0.232288%
> > > > 453.povray 6.70 6.72 0.298507%
> > > > 454.calculix 2.81 2.74 -2.4911%
> > > > 459.GemsFDTD 6.07 4.95 -18.4514%
> > > > 465.tonto 4.44 4.45 0.225225%
> > > > 470.lbm 10.6 10.7 0.943396%
> > > > 481.wrf 4.56 4.50 -1.31579%
> > > > 482.sphinx3 11.2 11.1 -0.892857%
> > > > Est. SPECfp_base2006 6.42 6.15 -4.20561%
> > > >
> > > > Evandro, what do you get on AMD?
> > > >
> > > > Is that related to recent i386 backend FP changes?
> >
> > Here's what we got:
> >
> > ?%
> > CPU2006
> > 410.bwaves -6%
> > 416.gamess
> > 433.milc
> > 434.zeusmp
> > 435.gromacs
> > 436.cactusADM
> > 437.leslie3d -26%
> > 444.namd
> > 447.dealII
> > 450.soplex
> > 453.povray
> > 454.calculix
> > 459.GemsFDTD -12%
> > 465.tonto
> > 470.lbm
> > 481.wrf
> > 482.sphinx3
> >
> > Though not as pronounced, definitely significant.
> >
>
> It is close to what we see on both x86 and x86-64. Are you going to
> track it down?
Just in case people are cherry picking the gcc mailing list and not
reading all of the threads, this is also discussed in this thread, where
it was felt that the PPRE patches that were added on November 13th were
the cause of the slowdown:
http://gcc.gnu.org/ml/gcc/2006-12/msg00023.html
Has anybody tried doing a run with just ppre disabled?