Re: [BENCHMARK] gcc3.2 v 2.95.3 (contest and linux-2.5.38)

Daniel Jacobowitz
2002-09-23T03:41:42Z

On Sun, Sep 22, 2002 at 08:41:51PM -0700, Andrew Morton wrote:
> Con Kolivas wrote:
> >
> > I performed contest benchmarks on kernel 2.5.38 when the kernel is compiled with
> > gcc3.2 to gcc2.95.3
> >
> > warning: The following benchmarks may be disturbing to some viewers:
> >
> > No Load:
> > Kernel Time CPU
> > 2.5.38 68.25 99%
> > 2.5.38-gcc32 103.03 99%
> >
>
> Try gcc-2.91.66. It might break the 45 second mark.
>
> > IO Full Load:
> > Kernel Time CPU
> > 2.5.38 170.21 42%
> > 2.5.38-gcc32 1405.25 8%
>
> The streaming write is stalling gcc's read for long enough for gcc's
> working set to be evicted. And the working set cannot be reestablished
> because the streaming write prevents it. Meltdown.
>
> I have fixed this. Hang around.

That sounds like a slowdown in _running_ GCC... The worrisome part of
Con's post is that he was talking about which compiler he'd built the
kernel with. Right?

--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer