From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [patch 09/17] LTTng instrumentation - filemap From: Peter Zijlstra In-Reply-To: <20080715222748.002421557@polymtl.ca> References: <20080715222604.331269462@polymtl.ca> <20080715222748.002421557@polymtl.ca> Content-Type: text/plain Date: Wed, 16 Jul 2008 10:35:34 +0200 Message-Id: <1216197334.5232.24.camel@twins> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Mathieu Desnoyers Cc: akpm@linux-foundation.org, Ingo Molnar , linux-kernel@vger.kernel.org, Masami Hiramatsu , linux-mm@kvack.org, Dave Hansen , "Frank Ch. Eigler" , Hideo AOKI , Takashi Nishiie , Steven Rostedt , Eduard - Gabriel Munteanu List-ID: On Tue, 2008-07-15 at 18:26 -0400, Mathieu Desnoyers wrote: > plain text document attachment (lttng-instrumentation-filemap.patch) > Instrumentation of waits caused by memory accesses on mmap regions. > > Those tracepoints are used by LTTng. > > About the performance impact of tracepoints (which is comparable to markers), > even without immediate values optimizations, tests done by Hideo Aoki on ia64 > show no regression. His test case was using hackbench on a kernel where > scheduler instrumentation (about 5 events in code scheduler code) was added. > See the "Tracepoints" patch header for performance result detail. > > Signed-off-by: Mathieu Desnoyers > CC: linux-mm@kvack.org > CC: Dave Hansen > CC: Masami Hiramatsu > CC: 'Peter Zijlstra' > CC: "Frank Ch. Eigler" > CC: 'Ingo Molnar' > CC: 'Hideo AOKI' > CC: Takashi Nishiie > CC: 'Steven Rostedt' > CC: Eduard - Gabriel Munteanu > --- > include/trace/filemap.h | 13 +++++++++++++ > mm/filemap.c | 3 +++ > 2 files changed, 16 insertions(+) > > Index: linux-2.6-lttng/mm/filemap.c > =================================================================== > --- linux-2.6-lttng.orig/mm/filemap.c 2008-07-15 14:51:50.000000000 -0400 > +++ linux-2.6-lttng/mm/filemap.c 2008-07-15 15:14:46.000000000 -0400 > @@ -33,6 +33,7 @@ > #include > #include /* for BUG_ON(!in_atomic()) only */ > #include > +#include > #include "internal.h" > > /* > @@ -541,9 +542,11 @@ void wait_on_page_bit(struct page *page, > { > DEFINE_WAIT_BIT(wait, &page->flags, bit_nr); > > + trace_filemap_wait_start(page, bit_nr); > if (test_bit(bit_nr, &page->flags)) > __wait_on_bit(page_waitqueue(page), &wait, sync_page, > TASK_UNINTERRUPTIBLE); > + trace_filemap_wait_end(page, bit_nr); > } > EXPORT_SYMBOL(wait_on_page_bit); I don't like the trace_filemap_wait_* naming.. trace_wait_on_page_* might make more sense > Index: linux-2.6-lttng/include/trace/filemap.h > =================================================================== > --- /dev/null 1970-01-01 00:00:00.000000000 +0000 > +++ linux-2.6-lttng/include/trace/filemap.h 2008-07-15 15:14:46.000000000 -0400 > @@ -0,0 +1,13 @@ > +#ifndef _TRACE_FILEMAP_H > +#define _TRACE_FILEMAP_H > + > +#include > + > +DEFINE_TRACE(filemap_wait_start, > + TPPROTO(struct page *page, int bit_nr), > + TPARGS(page, bit_nr)); > +DEFINE_TRACE(filemap_wait_end, > + TPPROTO(struct page *page, int bit_nr), > + TPARGS(page, bit_nr)); > + > +#endif > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org