linux/include/trace
Mel Gorman 0d3d062a6e tracing, page-allocator: add trace event for page traffic related to the buddy lists
The page allocation trace event reports that a page was successfully
allocated but it does not specify where it came from.  When analysing
performance, it can be important to distinguish between pages coming from
the per-cpu allocator and pages coming from the buddy lists as the latter
requires the zone lock to the taken and more data structures to be
examined.

This patch adds a trace event for __rmqueue reporting when a page is being
allocated from the buddy lists.  It distinguishes between being called to
refill the per-cpu lists or whether it is a high-order allocation.
Similarly, this patch adds an event to catch when the PCP lists are being
drained a little and pages are going back to the buddy lists.

This is trickier to draw conclusions from but high activity on those
events could explain why there were a large number of cache misses on a
page-allocator-intensive workload.  The coalescing and splitting of
buddies involves a lot of writing of page metadata and cache line bounces
not to mention the acquisition of an interrupt-safe lock necessary to
enter this path.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Li Ming Chun <macli@brc.ubc.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:34 -07:00
..
events tracing, page-allocator: add trace event for page traffic related to the buddy lists 2009-09-22 07:17:34 -07:00
boot.h tracing/fastboot: include missing headers 2008-12-12 09:26:13 +01:00
define_trace.h tracing: Undef TRACE_EVENT_FN between trace events headers inclusion 2009-08-27 18:32:54 +02:00
ftrace.h Merge branch 'perfcounters-rename-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-09-21 09:15:07 -07:00
power.h tracing: replace TP<var> with TP_<var> 2009-03-10 00:35:04 -04:00
syscall.h tracing: Create generic syscall TRACE_EVENTs 2009-08-26 00:41:48 +02:00