Re: [Qemu-devel] [RFC PATCH 0/2] port network layer onto glib

[Michael S. Tsirkin]

On Wed, Mar 13, 2013 at 06:31:57PM +0100, Paolo Bonzini wrote:
> > We could do that purely
> > with AioContexts as well, but that rules out a large class of
> > backends that offloaded event loops can interact with, such as Chardevs,
> > so I think modelling how to handle both will provide a threading model
> > that scales better with other devices/subsystems.
> 
> .. but I think the "no magic" argument applies here too.  After all we
> only have a handful of subsystems.  If chardevs are not performance
> critical, they can keep running in the main thread.
> 
> If one day we find out that we need a real-time serial port, and glib
> just doesn't cut it, we shouldn't be ashamed of ripping GIOChannels out,
> hand-writing the same stuff, and using a dedicated AioContext.  Of
> course by the time we get there we'll have unit tests/qtests to make
> sure we do not regress.  Right??? :)
> 
> Paolo

Since you mention serial port, just wanted to say that while it's
bandwidth requirements are not high, we do need to improve its latency.
ATM whenever someone tries to use the emulated serial, guest experiences
stalls and worst case latency jumps, and it's a pain point for many
users.

-- 
MST