On 12/04/2013 03:30 PM, Mel Gorman wrote:
This patch adds two tracepoints for compaction begin and end of a zone. Using
this it is possible to calculate how much time a workload is spending
within compaction and potentially debug problems related to cached pfns
for scanning.
I guess for debugging pfns it would be also useful to print their values
also in mm_compaction_end.
In combination with the direct reclaim and slab trace points
it should be possible to estimate most allocation-related overhead for
a workload.
Signed-off-by: Mel Gorman <[email protected]>
---
include/trace/events/compaction.h | 42 +++++++++++++++++++++++++++++++++++++++
mm/compaction.c | 4 ++++
2 files changed, 46 insertions(+)
diff --git a/include/trace/events/compaction.h
b/include/trace/events/compaction.h
index fde1b3e..f4e115a 100644
--- a/include/trace/events/compaction.h
+++ b/include/trace/events/compaction.h
@@ -67,6 +67,48 @@ TRACE_EVENT(mm_compaction_migratepages,
__entry->nr_failed)
);
+TRACE_EVENT(mm_compaction_begin,
+ TP_PROTO(unsigned long zone_start, unsigned long migrate_start,
+ unsigned long zone_end, unsigned long free_start),
+
+ TP_ARGS(zone_start, migrate_start, zone_end, free_start),
IMHO a better order would be:
zone_start, migrate_start, free_start, zone_end
(well especially in the TP_printk part anyway).
+
+ TP_STRUCT__entry(
+ __field(unsigned long, zone_start)
+ __field(unsigned long, migrate_start)
+ __field(unsigned long, zone_end)
+ __field(unsigned long, free_start)
+ ),
+
+ TP_fast_assign(
+ __entry->zone_start = zone_start;
+ __entry->migrate_start = migrate_start;
+ __entry->zone_end = zone_end;
+ __entry->free_start = free_start;
+ ),
+
+ TP_printk("zone_start=%lu migrate_start=%lu zone_end=%lu
free_start=%lu",
+ __entry->zone_start,
+ __entry->migrate_start,
+ __entry->zone_end,
+ __entry->free_start)
+);
+
+TRACE_EVENT(mm_compaction_end,
+ TP_PROTO(int status),
+
+ TP_ARGS(status),
+
+ TP_STRUCT__entry(
+ __field(int, status)
+ ),
+
+ TP_fast_assign(
+ __entry->status = status;
+ ),
+
+ TP_printk("status=%d", __entry->status)
+);
#endif /* _TRACE_COMPACTION_H */
diff --git a/mm/compaction.c b/mm/compaction.c
index c437893..78ff866 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -960,6 +960,8 @@ static int compact_zone(struct zone *zone, struct
compact_control *cc)
if (compaction_restarting(zone, cc->order) && !current_is_kswapd())
__reset_isolation_suitable(zone);
+ trace_mm_compaction_begin(start_pfn, cc->migrate_pfn, end_pfn,
cc->free_pfn);
+
migrate_prep_local();
while ((ret = compact_finished(zone, cc)) == COMPACT_CONTINUE) {
@@ -1005,6 +1007,8 @@ out:
cc->nr_freepages -= release_freepages(&cc->freepages);
VM_BUG_ON(cc->nr_freepages != 0);
+ trace_mm_compaction_end(ret);
+
return ret;
}
--
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