path: root/block/blk-cgroup.h
diff options
authorDivyesh Shah <dpshah@google.com>2010-04-08 21:15:35 -0700
committerJens Axboe <jens.axboe@oracle.com>2010-04-09 08:36:08 +0200
commit812df48d127365ffd0869aa139738f572a86759c (patch)
tree772ef559057cd432ad874cd429287e7a912b1bb3 /block/blk-cgroup.h
parentcdc1184cf4a7bd99f5473a91244197accc49146b (diff)
blkio: Add more debug-only per-cgroup stats
1) group_wait_time - This is the amount of time the cgroup had to wait to get a timeslice for one of its queues from when it became busy, i.e., went from 0 to 1 request queued. This is different from the io_wait_time which is the cumulative total of the amount of time spent by each IO in that cgroup waiting in the scheduler queue. This stat is a great way to find out any jobs in the fleet that are being starved or waiting for longer than what is expected (due to an IO controller bug or any other issue). 2) empty_time - This is the amount of time a cgroup spends w/o any pending requests. This stat is useful when a job does not seem to be able to use its assigned disk share by helping check if that is happening due to an IO controller bug or because the job is not submitting enough IOs. 3) idle_time - This is the amount of time spent by the IO scheduler idling for a given cgroup in anticipation of a better request than the exising ones from other queues/cgroups. All these stats are recorded using start and stop events. When reading these stats, we do not add the delta between the current time and the last start time if we're between the start and stop events. We avoid doing this to make sure that these numbers are always monotonically increasing when read. Since we're using sched_clock() which may use the tsc as its source, it may induce some inconsistency (due to tsc resync across cpus) if we included the current delta. Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-cgroup.h')
1 files changed, 54 insertions, 0 deletions
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index bea7f3b9a88..bfce085b196 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -43,6 +43,9 @@ enum stat_type {
@@ -55,6 +58,13 @@ enum stat_sub_type {
+/* blkg state flags */
+enum blkg_state_flags {
+ BLKG_waiting = 0,
+ BLKG_idling,
+ BLKG_empty,
struct blkio_cgroup {
struct cgroup_subsys_state css;
unsigned int weight;
@@ -74,6 +84,21 @@ struct blkio_group_stats {
uint64_t avg_queue_size_samples;
/* How many times this group has been removed from service tree */
unsigned long dequeue;
+ /* Total time spent waiting for it to be assigned a timeslice. */
+ uint64_t group_wait_time;
+ uint64_t start_group_wait_time;
+ /* Time spent idling for this blkio_group */
+ uint64_t idle_time;
+ uint64_t start_idle_time;
+ /*
+ * Total time when we have requests queued and do not contain the
+ * current active queue.
+ */
+ uint64_t empty_time;
+ uint64_t start_empty_time;
+ uint16_t flags;
@@ -137,12 +162,41 @@ static inline char *blkg_path(struct blkio_group *blkg)
void blkiocg_update_set_active_queue_stats(struct blkio_group *blkg);
void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue);
+void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg);
+void blkiocg_update_idle_time_stats(struct blkio_group *blkg);
+void blkiocg_set_start_empty_time(struct blkio_group *blkg, bool ignore);
+#define BLKG_FLAG_FNS(name) \
+static inline void blkio_mark_blkg_##name( \
+ struct blkio_group_stats *stats) \
+{ \
+ stats->flags |= (1 << BLKG_##name); \
+} \
+static inline void blkio_clear_blkg_##name( \
+ struct blkio_group_stats *stats) \
+{ \
+ stats->flags &= ~(1 << BLKG_##name); \
+} \
+static inline int blkio_blkg_##name(struct blkio_group_stats *stats) \
+{ \
+ return (stats->flags & (1 << BLKG_##name)) != 0; \
+} \
static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
static inline void blkiocg_update_set_active_queue_stats(
struct blkio_group *blkg) {}
static inline void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue) {}
+static inline void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
+static inline void blkiocg_update_idle_time_stats(struct blkio_group *blkg) {}
+static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg,
+ bool ignore) {}