Re: [Qemu-devel] Significant performance regression in qemu-system-mips.

[Aurelien Jarno <aurelien@aurel32.net>]

On Thu, Mar 25, 2010 at 12:33:33PM -0500, Rob Landley wrote:
> On Thursday 25 March 2010 04:20:26 Artyom Tarasenko wrote:
> > 2010/3/24 Rob Landley <rob@landley.net>:
> > > I have a native build under qemu that gets killed if it doesn't produce a
> > > line of output for 60 seconds (hang detection enforced by the host
> > > monitoring qemu's stdout with --nographic, not from within qemu).
> > >
> > > In the most recent release version, it never came close to triggering on
> > > mips with a 30 second timeout.  In the current -git version (well, as of
> > > Thursday anyway), it triggers frequently (about 90% of the time) even
> > > with a 60 second timeout.
> >
> > Are other platforms affected as well? Do your automated tests run
> > against qemu-sparc meanwhile?
> 
> That was the only platform I hit this particular regression on.  It affects 
> mips, mipsel, and mips64.
> 
> The arm, x86, and x86-64 targets built to the end just fine.
> 
> Sparc works fine from a performance perspective (the timeout doesn't trigger), 
> it just dies building strace with:
> 
>   In file included from file.c:88:^M
>   /usr/bin/../include/asm/stat.h:56: error: expected specifier-qualifier-list
>     before 'uid16_t'^
> 
> Which is either an strace bug or something wrong with the kernel headers, 
> either way I need too track that down and fix it.
> 
> Powerpc got broken by the 2.6.32->2.6.33 kernel upgrade (the hard drives don't 
> work because something broke in DMA interrupt handling, I'm bisecting it), so 
> I can't comment on its performance at the moment.  I'll get back to you on 
> that one.

This has been broken in r680 of openbios. I haven't found time to find
the real problem though.

> As far as I can tell the sh4 linux-kernel maintainer officially doesn't care 
> about anybody who isn't employed by his company, so I'm not sure I still care 
> about supporting that platform.  It's not real hardware, it's a one-company 
> toy:
> 
>   http://permalink.gmane.org/gmane.linux.ports.sh.devel/7233
>   http://permalink.gmane.org/gmane.linux.ports.sh.devel/7237
> 

If you continue to attack people like that, not sure I'll continue to
care about your emails. Your emails on this mailing list are always
complaining, and it really starts to be annoying.

Aurelien

-- 
Aurelien Jarno	                        GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net