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Re: gcc compile-time performance
- From: Richard Earnshaw <rearnsha at arm dot com>
- To: Jan Hubicka <jh at suse dot cz>
- Cc: Robert Dewar <dewar at gnat dot com>, Richard dot Earnshaw at arm dot com, gcc at gcc dot gnu dot org
- Date: Mon, 20 May 2002 16:24:49 +0100
- Subject: Re: gcc compile-time performance
- Organization: ARM Ltd.
- Reply-to: Richard dot Earnshaw at arm dot com
> > <<Yes, that is alternative. Will it be considerably faster than the current
> > FP emulation library doing the same?
> > >>
> > Oh yes, much faster, by a significant factor, which is all you need in this
> > case.
> Hmm, I still guess there are easier ways to cut of 1-1.5% (even with host FP
> the function was taking about 1% of compilation time due to CFG traversal and I
> doubt I can get faster. However I can try to do that after finals if this is
> considered usefull.
> (BTW I am still having problems to see it in the -Q dumps. Curisously enoght
> if I enable -fprofile-arcs, I get the branch probabilities printed, but not
> without it).
> On what machine do you do the measurements?
In this case a 6 cpu P3 box.
Note, I see very bizarre numbers from the -Q dumps also -- I don't think
the timers are returning small enough increments as the machines get
faster -- note that often we are getting zero complete clock ticks within
a single optimization.
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 10
model name : Pentium III (Cascades)
stepping : 1
cpu MHz : 700.061
cache size : 2048 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
cmov pat pse36 mmx fxsr sse
bogomips : 1395.91
processor : 1