From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id oAT0JGDg069826 for ; Sun, 28 Nov 2010 18:19:17 -0600 Received: from mail.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 4428613F3B26 for ; Sun, 28 Nov 2010 16:20:56 -0800 (PST) Received: from mail.internode.on.net (bld-mail12.adl6.internode.on.net [150.101.137.97]) by cuda.sgi.com with ESMTP id jpFpku2ceaVT2JgF for ; Sun, 28 Nov 2010 16:20:56 -0800 (PST) Received: from dastard (unverified [121.44.88.148]) by mail.internode.on.net (SurgeMail 3.8f2) with ESMTP id 48044421-1927428 for ; Mon, 29 Nov 2010 10:50:55 +1030 (CDT) Received: from [192.168.1.1] (helo=disappointment) by dastard with esmtp (Exim 4.71) (envelope-from ) id 1PMrUD-0000Vg-Rg for xfs@oss.sgi.com; Mon, 29 Nov 2010 11:20:53 +1100 Received: from dave by disappointment with local (Exim 4.72) (envelope-from ) id 1PMrTo-00049o-OZ for xfs@oss.sgi.com; Mon, 29 Nov 2010 11:20:28 +1100 From: Dave Chinner Subject: [PATCH 5/5] xfs: only run xfs_error_test if error injection is active Date: Mon, 29 Nov 2010 11:20:24 +1100 Message-Id: <1290990024-15898-6-git-send-email-david@fromorbit.com> In-Reply-To: <1290990024-15898-1-git-send-email-david@fromorbit.com> References: <1290990024-15898-1-git-send-email-david@fromorbit.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com From: Dave Chinner Recent tests writing lots of small files showed the flusher thread being CPU bound and taking a long time to do allocations on a debug kernel. perf showed this as the prime reason: samples pcnt function DSO _______ _____ ___________________________ _________________ 224648.00 36.8% xfs_error_test [kernel.kallsyms] 86045.00 14.1% xfs_btree_check_sblock [kernel.kallsyms] 39778.00 6.5% prandom32 [kernel.kallsyms] 37436.00 6.1% xfs_btree_increment [kernel.kallsyms] 29278.00 4.8% xfs_btree_get_rec [kernel.kallsyms] 27717.00 4.5% random32 [kernel.kallsyms] Walking btree blocks during allocation checking them requires each block (a cache hit, so no I/O) call xfs_error_test(), which then does a random32() call as the first operation. IOWs, ~50% of the CPU is being consumed just testing whether we need to inject an error, even though error injection is not active. Kill this overhead when error injection is not active by adding a global counter of active error traps and only calling into xfs_error_test when fault injection is active. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig --- fs/xfs/xfs_error.c | 3 +++ fs/xfs/xfs_error.h | 5 +++-- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c index ed99902..c78cc6a 100644 --- a/fs/xfs/xfs_error.c +++ b/fs/xfs/xfs_error.c @@ -58,6 +58,7 @@ xfs_error_trap(int e) int xfs_etest[XFS_NUM_INJECT_ERROR]; int64_t xfs_etest_fsid[XFS_NUM_INJECT_ERROR]; char * xfs_etest_fsname[XFS_NUM_INJECT_ERROR]; +int xfs_error_test_active; int xfs_error_test(int error_tag, int *fsidp, char *expression, @@ -108,6 +109,7 @@ xfs_errortag_add(int error_tag, xfs_mount_t *mp) len = strlen(mp->m_fsname); xfs_etest_fsname[i] = kmem_alloc(len + 1, KM_SLEEP); strcpy(xfs_etest_fsname[i], mp->m_fsname); + xfs_error_test_active++; return 0; } } @@ -137,6 +139,7 @@ xfs_errortag_clearall(xfs_mount_t *mp, int loud) xfs_etest_fsid[i] = 0LL; kmem_free(xfs_etest_fsname[i]); xfs_etest_fsname[i] = NULL; + xfs_error_test_active--; } } diff --git a/fs/xfs/xfs_error.h b/fs/xfs/xfs_error.h index c2c1a07..f338847 100644 --- a/fs/xfs/xfs_error.h +++ b/fs/xfs/xfs_error.h @@ -127,13 +127,14 @@ extern void xfs_corruption_error(const char *tag, int level, #define XFS_RANDOM_BMAPIFORMAT XFS_RANDOM_DEFAULT #ifdef DEBUG +extern int xfs_error_test_active; extern int xfs_error_test(int, int *, char *, int, char *, unsigned long); #define XFS_NUM_INJECT_ERROR 10 #define XFS_TEST_ERROR(expr, mp, tag, rf) \ - ((expr) || \ + ((expr) || (xfs_error_test_active && \ xfs_error_test((tag), (mp)->m_fixedfsid, "expr", __LINE__, __FILE__, \ - (rf))) + (rf)))) extern int xfs_errortag_add(int error_tag, xfs_mount_t *mp); extern int xfs_errortag_clearall(xfs_mount_t *mp, int loud); -- 1.7.2.3 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs