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

[Christian Borntraeger]

On 20/02/13 11:28, Stefan Hajnoczi wrote:
> Amos Kong <address@hidden> reported that file descriptors numbered higher
> than 1024 could crash QEMU.  This is due to the fixed size of the fd_set type
> used for select(2) event polling.
> 

Good to see somebody working on that.
We have just faced this problem on s390 after we have experimentally enabled 
ioeventfd
for virtio-ccw. We have several scenarios were we want > 600 devices for the 
guest
and the select loops then fails horribly because we exceed the 1024 fd barrier.

So this looks like it could become a bugfix for that problem.

In terms of scalability it is probably better to have multiple threads that 
poll on their 
fds, instead of having one i/o thread. 

Still this looks like a good thing to do.

Christian