Re: [Qemu-devel] [PATCH v3] glib: fix g_poll early timeout on windows

[Stefan Hajnoczi <stefanha@redhat.com>]

On Fri, Apr 18, 2014 at 08:24:03PM +0400, Stanislav Vorobiov wrote:
> From: Sangho Park <sangho1206.park@samsung.com>
> 
> g_poll has a problem on Windows when using
> timeouts < 10ms, in glib/gpoll.c:
> 
> /* If not, and we have a significant timeout, poll again with
>  * timeout then. Note that this will return indication for only
>  * one event, or only for messages. We ignore timeouts less than
>  * ten milliseconds as they are mostly pointless on Windows, the
>  * MsgWaitForMultipleObjectsEx() call will timeout right away
>  * anyway.
>  */
> if (retval == 0 && (timeout == INFINITE || timeout >= 10))
>   retval = poll_rest (poll_msgs, handles, nhandles, fds, nfds, timeout);
> 
> so whenever g_poll is called with timeout < 10ms it does
> a quick poll instead of wait, this causes significant performance
> degradation of QEMU, thus we should use WaitForMultipleObjectsEx
> directly
> 
> Signed-off-by: Stanislav Vorobiov <s.vorobiov@samsung.com>
> ---
>  include/glib-compat.h |   19 +++++++++
>  include/qemu-common.h |   12 ------
>  util/oslib-win32.c    |  112 +++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 131 insertions(+), 12 deletions(-)

What is the status of this patch?

I haven't followed the discussions around the issue but can review/merge
if there is agreement now.

Stefan