Messages in this thread | | | Subject | Re: [patch 09/17] LTTng instrumentation - filemap | From | Peter Zijlstra <> | Date | Wed, 16 Jul 2008 10:35:34 +0200 |
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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 <mathieu.desnoyers@polymtl.ca> > CC: linux-mm@kvack.org > CC: Dave Hansen <haveblue@us.ibm.com> > CC: Masami Hiramatsu <mhiramat@redhat.com> > CC: 'Peter Zijlstra' <peterz@infradead.org> > CC: "Frank Ch. Eigler" <fche@redhat.com> > CC: 'Ingo Molnar' <mingo@elte.hu> > CC: 'Hideo AOKI' <haoki@redhat.com> > CC: Takashi Nishiie <t-nishiie@np.css.fujitsu.com> > CC: 'Steven Rostedt' <rostedt@goodmis.org> > CC: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> > --- > 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 <linux/cpuset.h> > #include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */ > #include <linux/memcontrol.h> > +#include <trace/filemap.h> > #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 <linux/tracepoint.h> > + > +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 >
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