qemu/include/glib-compat.h
Sangho Park 5a007547df glib: fix g_poll early timeout on windows
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>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-05-09 20:57:35 +02:00

47 lines
1.1 KiB
C

/*
* GLIB Compatibility Functions
*
* Copyright IBM, Corp. 2013
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#ifndef QEMU_GLIB_COMPAT_H
#define QEMU_GLIB_COMPAT_H
#include <glib.h>
#if !GLIB_CHECK_VERSION(2, 14, 0)
static inline guint g_timeout_add_seconds(guint interval, GSourceFunc function,
gpointer data)
{
return g_timeout_add(interval * 1000, function, data);
}
#endif
#ifdef _WIN32
/*
* g_poll has a problem on Windows when using
* timeouts < 10ms, so use wrapper.
*/
#define g_poll(fds, nfds, timeout) g_poll_fixed(fds, nfds, timeout)
gint g_poll_fixed(GPollFD *fds, guint nfds, gint timeout);
#elif !GLIB_CHECK_VERSION(2, 20, 0)
/*
* Glib before 2.20.0 doesn't implement g_poll, so wrap it to compile properly
* on older systems.
*/
static inline gint g_poll(GPollFD *fds, guint nfds, gint timeout)
{
GMainContext *ctx = g_main_context_default();
return g_main_context_get_poll_func(ctx)(fds, nfds, timeout);
}
#endif
#endif