Re: [Qemu-devel] [PATCH v4 00/10] main-loop: switch to g_poll(3) on POSIX hosts

[Paolo Bonzini]

Il 20/02/2013 15:56, Michael S. Tsirkin ha scritto:
> > I have tested that the series builds and is bisectable on Linux and Windows
> > hosts.  But I have not done extensive testing on other host platforms or 
> > with
> > long-term guests to check for performance regressions.
> 
> Wouldn't it make sense to switch to epoll instead?
> poll does not scale well to a huge number of descriptors.

At least for the block layer, where we want to go is to distribute the
performance-sensitive work to many independent dataplane threads.  Then
each of them could use epoll (basically a new aio-linux.c file based on
aio-posix.c), like hw/dataplane does already IIRC.  Only low-priority
tasks are left to the iothread.

The required work to get there would really be a superset of this, and
this series is a very good start.

Paolo