From patchwork Thu Aug 8 21:42:02 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Bligh X-Patchwork-Id: 265822 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (unknown [IPv6:2001:4830:134:3::12]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 91C942C0084 for ; Fri, 9 Aug 2013 07:43:53 +1000 (EST) Received: from localhost ([::1]:49659 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V7Xzr-0006qV-HK for incoming@patchwork.ozlabs.org; Thu, 08 Aug 2013 17:43:51 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54608) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V7Xyr-0006J4-V2 for qemu-devel@nongnu.org; Thu, 08 Aug 2013 17:42:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V7Xyp-0006zr-KP for qemu-devel@nongnu.org; Thu, 08 Aug 2013 17:42:49 -0400 Received: from mail.avalus.com ([2001:41c8:10:1dd::10]:53785) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V7Xyp-0006xz-Es for qemu-devel@nongnu.org; Thu, 08 Aug 2013 17:42:47 -0400 Received: by mail.avalus.com (Postfix) with ESMTPSA id B02BDC561AF; Thu, 8 Aug 2013 22:42:46 +0100 (BST) From: Alex Bligh To: qemu-devel@nongnu.org Date: Thu, 8 Aug 2013 22:42:02 +0100 Message-Id: <1375998147-24292-6-git-send-email-alex@alex.org.uk> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1375998147-24292-1-git-send-email-alex@alex.org.uk> References: <1375998147-24292-1-git-send-email-alex@alex.org.uk> X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2001:41c8:10:1dd::10 Cc: Kevin Wolf , Anthony Liguori , Alex Bligh , liu ping fan , Stefan Hajnoczi , Paolo Bonzini , MORITA Kazutaka , rth@twiddle.net Subject: [Qemu-devel] [RFC] [PATCHv8 05/30] aio / timers: Add prctl(PR_SET_TIMERSLACK, 1, ...) to reduce timer slack X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Where supported, called prctl(PR_SET_TIMERSLACK, 1, ...) to set one nanosecond timer slack to increase precision of timer calls. Signed-off-by: Alex Bligh --- qemu-timer.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/qemu-timer.c b/qemu-timer.c index 5e81935..9eb6db8 100644 --- a/qemu-timer.c +++ b/qemu-timer.c @@ -41,6 +41,10 @@ #include #endif +#ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK +#include +#endif + /***********************************************************/ /* timers */ @@ -507,6 +511,9 @@ void init_clocks(void) vm_clock = qemu_clock_new(QEMU_CLOCK_VIRTUAL); host_clock = qemu_clock_new(QEMU_CLOCK_HOST); } +#ifdef CONFIG_PRCTL_PR_SET_TIMERSLACK + prctl(PR_SET_TIMERSLACK, 1, 0, 0, 0); +#endif } uint64_t qemu_timer_expire_time_ns(QEMUTimer *ts)