From patchwork Thu Sep 29 02:43:55 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Chubb X-Patchwork-Id: 116883 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [140.186.70.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id C0A2CB6F9C for ; Thu, 29 Sep 2011 12:44:14 +1000 (EST) Received: from localhost ([::1]:39565 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R96ba-0005N9-Ty for incoming@patchwork.ozlabs.org; Wed, 28 Sep 2011 22:44:10 -0400 Received: from eggs.gnu.org ([140.186.70.92]:50761) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R96bU-0005N2-EU for qemu-devel@nongnu.org; Wed, 28 Sep 2011 22:44:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1R96bT-0004Tv-01 for qemu-devel@nongnu.org; Wed, 28 Sep 2011 22:44:04 -0400 Received: from lemon.ertos.nicta.com.au ([203.143.174.143]:38014 helo=lemon.ken.nicta.com.au) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R96bS-0004Tb-J6 for qemu-devel@nongnu.org; Wed, 28 Sep 2011 22:44:02 -0400 Received: from [2001:388:d000:800:21d:e0ff:fe35:2bed] (port=35843 helo=croc.chubb.wattle.id.au) by lemon.ken.nicta.com.au with esmtpsa (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.72) (envelope-from ) id 1R96bM-0007Js-7I; Thu, 29 Sep 2011 12:43:59 +1000 Date: Thu, 29 Sep 2011 12:43:55 +1000 Message-ID: From: Peter Chubb To: qemu-devel@nongnu.org User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/23.3 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) X-Face: GgFg(Z>fx((4\32hvXq<)|jndSniCH~~$D)Ka:P@e@JR1P%Vr}EwUdfwf-4j\rUs#JR{'h# !]])6%Jh~b$VA|ALhnpPiHu[-x~@<"@Iv&|%R)Fq[[, (&Z'O)Q)xCqe1\M[F8#9l8~}#u$S$Rm`S9% \'T@`:&8>Sb*c5d'=eDYI&GF`+t[LfDH="MP5rwOO]w>ALi7'=QJHz&y&C&TE_3j! Organization: National ICT Australia MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") X-SA-Exim-Connect-IP: 2001:388:d000:800:21d:e0ff:fe35:2bed X-SA-Exim-Mail-From: peter.chubb@nicta.com.au X-SA-Exim-Version: 4.2.1 (built Mon, 22 Mar 2010 06:52:44 +0000) X-SA-Exim-Scanned: Yes (on lemon.ken.nicta.com.au) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 203.143.174.143 Cc: bernard.blackham@nicta.com.au, philipo@ok-labs.com Subject: [Qemu-devel] [PATCH] Remove line buffering from log file 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 This patch was originally written by Bernard Blackham, and modified by Peter Chubb. From 0d755af2f5bef22432da71f2fe0a9dce7d2882cd Mon Sep 17 00:00:00 2001 From: Bernard Blackham Date: Fri, 24 Jul 2009 13:38:03 +1000 Subject: Disable line-based log buffering. There's no real reason for line-based buffering in log file output. If block buffering with a decent sized buffer is used, it can speed qemu up for -d all or -d exec significantly. The only thing you lose is that the last up to 4k of log output may be lost if qemu crashes. Signed-off-by: Peter Chubb Signed-off-by: Hans Jang Signed-off-by: Bernard Blackham --- exec.c | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-) -- Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au http://www.ertos.nicta.com.au ERTOS within National ICT Australia Index: qemu-working/exec.c =================================================================== --- qemu-working.orig/exec.c 2011-09-29 09:03:35.866233828 +1000 +++ qemu-working/exec.c 2011-09-29 12:40:56.668973550 +1000 @@ -1594,29 +1594,28 @@ void cpu_single_step(CPUState *env, int /* enable or disable low levels log */ void cpu_set_log(int log_flags) { loglevel = log_flags; if (loglevel && !logfile) { logfile = fopen(logfilename, log_append ? "a" : "w"); if (!logfile) { perror(logfilename); _exit(1); } + +/* Don't use line-based buffering: it hurts -d exec */ #if !defined(CONFIG_SOFTMMU) /* must avoid mmap() usage of glibc by setting a buffer "by hand" */ { static char logfile_buf[4096]; - setvbuf(logfile, logfile_buf, _IOLBF, sizeof(logfile_buf)); + setvbuf(logfile, logfile_buf, _IOFBF, sizeof(logfile_buf)); } -#elif !defined(_WIN32) - /* Win32 doesn't support line-buffering and requires size >= 2 */ - setvbuf(logfile, NULL, _IOLBF, 0); #endif log_append = 1; } if (!loglevel && logfile) { fclose(logfile); logfile = NULL; } } void cpu_set_log_filename(const char *filename)