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

[Con Kolivas]

Quoting Daniel Jacobowitz <[e-mail]>:

> 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?

Correct. contest was run with gcc2.95.3 only. The kernels were compiled with
2.95.3 and 3.2 respectively.

Con.