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Re: Compilation performance comparison of gcc3.4.1 and gcc3.5.0 2004-08-30 on MICO sources
On Tuesday 31 August 2004 12:50, Paolo Bonzini wrote:
> > 3.4.1:
> > expand : 0.79 ( 6%) usr 0.03 ( 1%) sys 0.78 ( 5%)
> >
> > 3.5.0-HEAD:
> > expand : 2.08 ( 9%) usr 0.07 ( 4%) sys 2.51 (10%)
> > wall
>
> Also:
>
> 3.4.1:
> integration : 0.65 ( 5%) usr 0.00 ( 0%) sys 0.67 ( 4%) wall
> global alloc : 0.91 ( 6%) usr 0.02 ( 1%) sys 0.83 ( 5%) wall
>
> 3.5.0-HEAD:
> integration : 1.01 ( 4%) usr 0.06 ( 3%) sys 0.88 ( 3%) wall
> global alloc : 1.16 ( 5%) usr 0.01 ( 1%) sys 1.34 ( 5%) wall
>
> This is overall +0.5 seconds, which another 4%. And then:
This may also just be noise. Some passes run so fast that the
time vars are not accurate enough to record it. You'll see that
for bodies of code with many small functions, -ftime-report will
give a very different TOTAL than /usr/bin/time ;-)
> The -O2 times for 3.5 would help as well, I suspect -funit-at-a-time is
> helping a lot.
Rather the other way around, since GCC 3.5 has -funit-at-a-time
enabled for C++ at -O0.
Gr.
Steven