From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:60141) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TEEfq-0008Nn-Jl for qemu-devel@nongnu.org; Wed, 19 Sep 2012 03:26:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TEEfm-0004zK-F0 for qemu-devel@nongnu.org; Wed, 19 Sep 2012 03:26:18 -0400 Received: from mail-wi0-f175.google.com ([209.85.212.175]:52397) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TEEfm-0004y6-88 for qemu-devel@nongnu.org; Wed, 19 Sep 2012 03:26:14 -0400 Received: by wibhm2 with SMTP id hm2so3800519wib.10 for ; Wed, 19 Sep 2012 00:26:13 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <5059738E.5070004@redhat.com> Date: Wed, 19 Sep 2012 09:26:06 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1348000626-16129-1-git-send-email-aliguori@us.ibm.com> In-Reply-To: <1348000626-16129-1-git-send-email-aliguori@us.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] qemu-clock: add an alarm timer based on timerfd List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Jan Kiszka , qemu-devel@nongnu.org, Peter Portante , Stefan Weil Il 18/09/2012 22:37, Anthony Liguori ha scritto: > Unfortunately, there's a lot of Windows code in qemu-timer.c and main-loop.c > right now otherwise the refactoring would be trivial. I'll leave that for > another day. > > Cc: Paolo Bonzini > Cc: Jan Kiszka > Signed-off-by: Anthony Liguori > --- > Please note, this is lightly tested. Since this is such a fundamental change, > I'd like to do some performance analysis before committing but wanted to share > early. Looks good. I think Peter Portante tested something similar, and found no big difference between the two. But it's a good thing and, in my opinion, for non-timerfd OSes we should simply adjust the select() timeout and not bother with signals. I'm not sure if the same can be done for Windows, but I think it's possible as long as you keep the timeBeginPeriod/timeEndPeriod calls. As a start, Stefan, can you check if the win32 timer works for you with the calls added? Like this: diff --git a/qemu-timer.c b/qemu-timer.c index c7a1551..721c769 100644 --- a/qemu-timer.c +++ b/qemu-timer.c @@ -673,6 +673,10 @@ static int win32_start_timer(struct qemu_alarm_timer *t) HANDLE hTimer; BOOLEAN success; + timeGetDevCaps(&mm_tc, sizeof(mm_tc)); + + timeBeginPeriod(mm_tc.wPeriodMin); + /* If you call ChangeTimerQueueTimer on a one-shot timer (its period is zero) that has already expired, the timer is not updated. Since creating a new timer is relatively expensive, set a bogus one-hour @@ -688,6 +692,7 @@ static int win32_start_timer(struct qemu_alarm_timer *t) if (!success) { fprintf(stderr, "Failed to initialize win32 alarm timer: %ld\n", GetLastError()); + timeEndPeriod(mm_tc.wPeriodMin); return -1; } @@ -702,6 +707,7 @@ static void win32_stop_timer(struct qemu_alarm_timer *t) if (hTimer) { DeleteTimerQueueTimer(NULL, hTimer, NULL); } + timeEndPeriod(mm_tc.wPeriodMin); } static void win32_rearm_timer(struct qemu_alarm_timer *t, Paolo