Re: [Qemu-devel] Re: [PATCH] QEMUFileBuffered: indicate that we're ready when the underlying file is ready

[Luiz Capitulino <lcapitulino@redhat.com>]

On Tue, 03 Aug 2010 09:12:52 +0300
Avi Kivity <avi@redhat.com> wrote:

>   On 07/07/2010 07:44 PM, Avi Kivity wrote:
> > QEMUFileBuffered stops writing when the underlying QEMUFile is not ready,
> > and tells its producer so.  However, when the underlying QEMUFile becomes
> > ready, it neglects to pass that information along, resulting in stoppage
> > of all data until the next tick (a tenths of a second).
> >
> > Usually this doesn't matter, because most QEMUFiles used with QEMUFileBuffered
> > are almost always ready, but in the case of exec: migration this is not true,
> > due to the small pipe buffers used to connect to the target process.  The
> > result is very slow migration.
> >
> > Fix by detecting the readiness notification and propagating it.  The detection
> > is a little ugly since QEMUFile overloads put_buffer() to send it, but that's
> > the suject for a different patch.
> 
> Ping.

I've queued this fix and another one in a 'for-0.13' branch and was planning
to send a pull request as soon as Anthony called for 0.13 fixes, however
this didn't happen yet and I forgot.