Re: [Qemu-devel] [PATCH v2] posix-aio-compat: fix latency issues

[Avi Kivity <avi@redhat.com>]

On 08/23/2011 05:10 PM, Jan Kiszka wrote:
> On 2011-08-23 16:02, Anthony Liguori wrote:
> >  On 08/23/2011 08:02 AM, Jan Kiszka wrote:
> >>  On 2011-08-23 14:40, Anthony Liguori wrote:
> >>>  You should be able to just use an eventfd or pipe.
> >>>
> >>>  Better yet, we should look at using GThreadPool to replace posix-aio-compat.
> >>
> >>  When interacting with the thread pool is part of some time-critical path
> >>  (easily possible with a real-time Linux guest), general-purpose
> >>  implementations like what glib offers are typically out of the game.
> >>  They do not provide sufficient customizability, specifically control
> >>  over their internal synchronization and allocation policies. That
> >>  applies to the other rather primitive glib threading and locking
> >>  services as well.
> >
> >  We can certainly enhance glib.  glib is a cross platform library.  I
>
> Do you want to carry forked glib bits in QEMU?

We can make real-time depend on a newer glib version.

>
> >  don't see a compelling reason to invent a new cross platform library
> >  just for QEMU especially if the justification is future features, not
> >  current features.
>
> Tweaking affinity of aio threads is already a current requirement.
>
> And we already have a working threading and locking system. One that is
> growing beyond glib's level of support quickly (think of RCU).
>

glib will have to support RCU as well.  But for this topic, I agree with 
you for now.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.