From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761955AbYC0NdA (ORCPT ); Thu, 27 Mar 2008 09:33:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760301AbYC0Nb0 (ORCPT ); Thu, 27 Mar 2008 09:31:26 -0400 Received: from smtp.polymtl.ca ([132.207.4.11]:52615 "EHLO smtp.polymtl.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757908AbYC0NbZ (ORCPT ); Thu, 27 Mar 2008 09:31:25 -0400 Message-Id: <20080327133015.159469909@polymtl.ca> References: <20080327132057.449831367@polymtl.ca> User-Agent: quilt/0.46-1 Date: Thu, 27 Mar 2008 09:21:04 -0400 From: Mathieu Desnoyers To: akpm@linux-foundation.org, linux-kernel@vger.kernel.org Cc: Mike Mason , David Wilder , Mathieu Desnoyers Subject: [patch for 2.6.26 7/7] LTTng instrumentation - lib Content-Disposition: inline; filename=lttng-instrumentation-lib.patch X-Poly-FromMTA: (dijkstra.casi.polymtl.ca [132.207.72.10]) at Thu, 27 Mar 2008 13:30:15 +0000 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (Originally : Add Markers into Semaphore Primitives) This patch adds several markers around semaphore primitives. Along with a tracing application this patch can be useful for measuring kernel semaphore usage and contention. Added markers : sem_down sem_down_intr sem_down_intr_fail sem_down_intr_resume sem_down_intr_sched sem_down_resume sem_down_sched sem_up Signed-off-by: Mike Mason Signed-off-by: David Wilder Signed-off-by: Mathieu Desnoyers --- lib/semaphore-sleepers.c | 9 +++++++++ 1 file changed, 9 insertions(+) Index: linux-2.6-lttng/lib/semaphore-sleepers.c =================================================================== --- linux-2.6-lttng.orig/lib/semaphore-sleepers.c 2008-03-27 08:08:37.000000000 -0400 +++ linux-2.6-lttng/lib/semaphore-sleepers.c 2008-03-27 08:08:56.000000000 -0400 @@ -15,6 +15,7 @@ #include #include #include +#include #include /* @@ -50,6 +51,7 @@ void __up(struct semaphore *sem) { + trace_mark(sem_up, "%p", sem); wake_up(&sem->wait); } @@ -59,6 +61,7 @@ void __sched __down(struct semaphore *se DECLARE_WAITQUEUE(wait, tsk); unsigned long flags; + trace_mark(sem_down, "%p", sem); tsk->state = TASK_UNINTERRUPTIBLE; spin_lock_irqsave(&sem->wait.lock, flags); add_wait_queue_exclusive_locked(&sem->wait, &wait); @@ -73,12 +76,14 @@ void __sched __down(struct semaphore *se * the wait_queue_head. */ if (!atomic_add_negative(sleepers - 1, &sem->count)) { + trace_mark(sem_down_resume, "%p", sem); sem->sleepers = 0; break; } sem->sleepers = 1; /* us - see -1 above */ spin_unlock_irqrestore(&sem->wait.lock, flags); + trace_mark(sem_down_sched, "%p", sem); schedule(); spin_lock_irqsave(&sem->wait.lock, flags); @@ -97,6 +102,7 @@ int __sched __down_interruptible(struct DECLARE_WAITQUEUE(wait, tsk); unsigned long flags; + trace_mark(sem_down_intr, "%p", sem); tsk->state = TASK_INTERRUPTIBLE; spin_lock_irqsave(&sem->wait.lock, flags); add_wait_queue_exclusive_locked(&sem->wait, &wait); @@ -113,6 +119,7 @@ int __sched __down_interruptible(struct * and exit. */ if (signal_pending(current)) { + trace_mark(sem_down_intr_fail, "%p", sem); retval = -EINTR; sem->sleepers = 0; atomic_add(sleepers, &sem->count); @@ -126,12 +133,14 @@ int __sched __down_interruptible(struct * still hoping to get the semaphore. */ if (!atomic_add_negative(sleepers - 1, &sem->count)) { + trace_mark(sem_down_intr_resume, "%p", sem); sem->sleepers = 0; break; } sem->sleepers = 1; /* us - see -1 above */ spin_unlock_irqrestore(&sem->wait.lock, flags); + trace_mark(sem_down_intr_sched, "%p", sem); schedule(); spin_lock_irqsave(&sem->wait.lock, flags); -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68