On w32, glib implements g_poll using WaitForMultipleObjects
or MsgWaitForMultipleObjects. This means that we can simplify
our code by switching to g_poll, and at the same time prepare for
adding back glib sources.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Right now, the main loop is not interrupted when data arrives on a
socket. To fix this, register each socket to interrupt the main loop
with WSAEventSelect. This does not replace select, it only communicates
a change in socket state that requires a select call.
Since the interrupt fires only once per recv call, or only once
after a send call returns EWOULDBLOCK we can activate it on all events
unconditionally. If QEMU is momentarily uninterested on some condition,
the main loop will not busy wait. Instead, it may get one extra wakeup,
but then it will ignore the condition until progress occurs and/or
qemu_set_fd_handler is called to set a callback. At this point the
condition will be tested via select and the callback will be invoked
even if it is still disabled on the event.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Using select with glib pollfds is wrong under w32. Restrict
the code to the POSIX case.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
The timeval-based timeout is not needed until we actually invoke select,
so compute it only then. Also group the two calls that modify the
timeout, glib_select_fill and os_host_main_loop_wait.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
In some cases initializing the alarm timers can lead to non-negligable
overhead from programs that link against qemu-tool.o. At least,
setting a max-resolution WinMM alarm timer via mm_start_timer() (the
current default for Windows) can increase the "tick rate" on Windows
OSs and affect frequency scaling, and in the case of tools that run
in guest OSs such has qemu-ga, the impact can be fairly dramatic
(+20%/20% user/sys time on a core 2 processor was observed from an idle
Windows XP guest).
This patch doesn't address the issue directly (not sure what a good
solution would be for Windows, or what other situations it might be
noticeable), but it at least limits the scope of the issue to programs
that "opt-in" to using the main-loop.c functions by only enabling alarm
timers when qemu_init_main_loop() is called, which is already required
to make use of those facilities, so existing users shouldn't be
affected.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The __attribute__((constructor)) init_main_loop() automatically get
called if qemu-tool.o is linked in. On win32, this leads to
a qemu_notify_event() call which attempts to SetEvent() on a HANDLE that
won't be initialized until qemu_init_main_loop() is manually called,
breaking qemu-tools.o programs on Windows at runtime.
This patch checks for an initialized event handle before attempting to
set it, which is analoguous to how we deal with an unitialized
io_thread_fd in the posix implementation.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
stdint.h defines the POSIX data types and is needed
for MinGW-w64 (and maybe other hosts).
v2: Instead of adding stdint.h directly, qemu-common.h is now
included and duplicate include statements were removed.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
