From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764110AbZDII4P (ORCPT ); Thu, 9 Apr 2009 04:56:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760921AbZDIIy0 (ORCPT ); Thu, 9 Apr 2009 04:54:26 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:55937 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758400AbZDIIyY (ORCPT ); Thu, 9 Apr 2009 04:54:24 -0400 Message-Id: <20090409085524.427173196@chello.nl> References: <20090409085342.799915215@chello.nl> User-Agent: quilt/0.46-1 Date: Thu, 09 Apr 2009 10:53:44 +0200 From: Peter Zijlstra To: Ingo Molnar Cc: Paul Mackerras , Corey Ashford , linux-kernel@vger.kernel.org, Peter Zijlstra Subject: [PATCH 2/4] perf_counter: optimize mmap/comm tracking Content-Disposition: inline; filename=perf_counter-opt-tracing.patch X-Bad-Reply: References but no 'Re:' in Subject. Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The mmap/comm tracking code does quite a lot of work before it discovers there's no interest in it, avoid that by keeping a counter. Signed-off-by: Peter Zijlstra --- kernel/perf_counter.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) Index: linux-2.6/kernel/perf_counter.c =================================================================== --- linux-2.6.orig/kernel/perf_counter.c +++ linux-2.6/kernel/perf_counter.c @@ -38,6 +38,10 @@ int perf_max_counters __read_mostly = 1; static int perf_reserved_percpu __read_mostly; static int perf_overcommit __read_mostly = 1; +static atomic_t nr_mmap_tracking __read_mostly; +static atomic_t nr_munmap_tracking __read_mostly; +static atomic_t nr_comm_tracking __read_mostly; + /* * Mutex for (sysadmin-configurable) counter reservations: */ @@ -1186,6 +1190,13 @@ static void free_counter(struct perf_cou { perf_pending_sync(counter); + if (counter->hw_event.mmap) + atomic_dec(&nr_mmap_tracking); + if (counter->hw_event.munmap) + atomic_dec(&nr_munmap_tracking); + if (counter->hw_event.comm) + atomic_dec(&nr_comm_tracking); + if (counter->destroy) counter->destroy(counter); @@ -2128,7 +2139,12 @@ got_name: void perf_counter_mmap(unsigned long addr, unsigned long len, unsigned long pgoff, struct file *file) { - struct perf_mmap_event mmap_event = { + struct perf_mmap_event mmap_event; + + if (!atomic_read(&nr_mmap_tracking)) + return; + + mmap_event = (struct perf_mmap_event){ .file = file, .event = { .header = { .type = PERF_EVENT_MMAP, }, @@ -2146,7 +2162,12 @@ void perf_counter_mmap(unsigned long add void perf_counter_munmap(unsigned long addr, unsigned long len, unsigned long pgoff, struct file *file) { - struct perf_mmap_event mmap_event = { + struct perf_mmap_event mmap_event; + + if (!atomic_read(&nr_munmap_tracking)) + return; + + mmap_event = (struct perf_mmap_event){ .file = file, .event = { .header = { .type = PERF_EVENT_MUNMAP, }, @@ -2725,6 +2746,13 @@ done: counter->hw_ops = hw_ops; + if (counter->hw_event.mmap) + atomic_inc(&nr_mmap_tracking); + if (counter->hw_event.munmap) + atomic_inc(&nr_munmap_tracking); + if (counter->hw_event.comm) + atomic_inc(&nr_comm_tracking); + return counter; } --