[PATCH] Add unaccounted time to timeslice_used.

Justin TerAvest
2011-03-11T21:06:34Z

There are two kind of times that tasks are not charged for: the first
seek and the extra time slice used over the allocated timeslice. Both
of these exported as a new unaccounted_time stat.

I think it would be good to have this reported in 'time' as well, but
that is probably a separate discussion.

Signed-off-by: Justin TerAvest <teravest@google.com>
---
block/blk-cgroup.c | 16 +++++++++++++++-
block/blk-cgroup.h | 12 ++++++++++--
block/cfq-iosched.c | 21 +++++++++++++--------
block/cfq.h | 6 +++---
4 files changed, 41 insertions(+), 14 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 455768a..77ee3c1 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -371,12 +371,14 @@ void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
}
EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats);

-void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time)
+void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time,
+ unsigned long unaccounted_time)
{
unsigned long flags;

spin_lock_irqsave(&blkg->stats_lock, flags);
blkg->stats.time += time;
+ blkg->stats.unaccounted_time += unaccounted_time;
spin_unlock_irqrestore(&blkg->stats_lock, flags);
}
EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
@@ -603,6 +605,9 @@ static uint64_t blkio_get_stat(struct blkio_group *blkg,
if (type == BLKIO_STAT_SECTORS)
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
blkg->stats.sectors, cb, dev);
+ if (type == BLKIO_STAT_UNACCOUNTED_TIME)
+ return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
+ blkg->stats.unaccounted_time, cb, dev);
#ifdef CONFIG_DEBUG_BLK_CGROUP
if (type == BLKIO_STAT_AVG_QUEUE_SIZE) {
uint64_t sum = blkg->stats.avg_queue_size_sum;
@@ -1106,6 +1111,9 @@ static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft,
case BLKIO_PROP_sectors:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_SECTORS, 0);
+ case BLKIO_PROP_unaccounted_time:
+ return blkio_read_blkg_stats(blkcg, cft, cb,
+ BLKIO_STAT_UNACCOUNTED_TIME, 0);
case BLKIO_PROP_io_service_bytes:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_SERVICE_BYTES, 1);
@@ -1262,6 +1270,12 @@ struct cftype blkio_files[] = {
.read_map = blkiocg_file_read_map,
},
{
+ .name = "unaccounted_time",
+ .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+ BLKIO_PROP_unaccounted_time),
+ .read_map = blkiocg_file_read_map,
+ },
+ {
.name = "io_service_bytes",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_io_service_bytes),
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index ea4861b..d71409e 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -49,6 +49,8 @@ enum stat_type {
/* All the single valued stats go below this */
BLKIO_STAT_TIME,
BLKIO_STAT_SECTORS,
+ /* Time not charged to this cgroup */
+ BLKIO_STAT_UNACCOUNTED_TIME,
#ifdef CONFIG_DEBUG_BLK_CGROUP
BLKIO_STAT_AVG_QUEUE_SIZE,
BLKIO_STAT_IDLE_TIME,
@@ -81,6 +83,7 @@ enum blkcg_file_name_prop {
BLKIO_PROP_io_serviced,
BLKIO_PROP_time,
BLKIO_PROP_sectors,
+ BLKIO_PROP_unaccounted_time,
BLKIO_PROP_io_service_time,
BLKIO_PROP_io_wait_time,
BLKIO_PROP_io_merged,
@@ -114,6 +117,8 @@ struct blkio_group_stats {
/* total disk time and nr sectors dispatched by this group */
uint64_t time;
uint64_t sectors;
+ /* Time not charged to this cgroup */
+ uint64_t unaccounted_time;
uint64_t stat_arr[BLKIO_STAT_QUEUED + 1][BLKIO_STAT_TOTAL];
#ifdef CONFIG_DEBUG_BLK_CGROUP
/* Sum of number of IOs queued across all samples */
@@ -293,7 +298,8 @@ extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
void *key);
void blkiocg_update_timeslice_used(struct blkio_group *blkg,
- unsigned long time);
+ unsigned long time,
+ unsigned long unaccounted_time);
void blkiocg_update_dispatch_stats(struct blkio_group *blkg, uint64_t bytes,
bool direction, bool sync);
void blkiocg_update_completion_stats(struct blkio_group *blkg,
@@ -319,7 +325,9 @@ blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
static inline struct blkio_group *
blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
- unsigned long time) {}
+ unsigned long time,
+ unsigned long unaccounted_time)
+{}
static inline void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
uint64_t bytes, bool direction, bool sync) {}
static inline void blkiocg_update_completion_stats(struct blkio_group *blkg,
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 7be4c79..0ba1e5c 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -909,7 +909,8 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
cfq_blkiocg_update_dequeue_stats(&cfqg->blkg, 1);
}

-static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq)
+static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq,
+ unsigned int *unaccounted_time)
{
unsigned int slice_used;

@@ -928,8 +929,13 @@ static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq)
1);
} else {
slice_used = jiffies - cfqq->slice_start;
- if (slice_used > cfqq->allocated_slice)
+ if (slice_used > cfqq->allocated_slice) {
+ *unaccounted_time = slice_used - cfqq->allocated_slice;
slice_used = cfqq->allocated_slice;
+ }
+ if (time_after(cfqq->slice_start, cfqq->dispatch_start))
+ *unaccounted_time += cfqq->slice_start -
+ cfqq->dispatch_start;
}

return slice_used;
@@ -939,12 +945,12 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
struct cfq_queue *cfqq)
{
struct cfq_rb_root *st = &cfqd->grp_service_tree;
- unsigned int used_sl, charge;
+ unsigned int used_sl, charge, unaccounted_sl = 0;
int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg)
- cfqg->service_tree_idle.count;

BUG_ON(nr_sync < 0);
- used_sl = charge = cfq_cfqq_slice_usage(cfqq);
+ used_sl = charge = cfq_cfqq_slice_usage(cfqq, &unaccounted_sl);

if (iops_mode(cfqd))
charge = cfqq->slice_dispatch;
@@ -970,7 +976,8 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u disp=%u charge=%u iops=%u"
" sect=%u", used_sl, cfqq->slice_dispatch, charge,
iops_mode(cfqd), cfqq->nr_sectors);
- cfq_blkiocg_update_timeslice_used(&cfqg->blkg, used_sl);
+ cfq_blkiocg_update_timeslice_used(&cfqg->blkg, used_sl,
+ unaccounted_sl);
cfq_blkiocg_set_start_empty_time(&cfqg->blkg);
}

@@ -3314,9 +3321,7 @@ static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
BUG_ON(!cfq_cfqq_on_rr(cfqq));

cfq_service_tree_add(cfqd, cfqq, 1);
-
- cfqq->slice_end = 0;
- cfq_mark_cfqq_slice_new(cfqq);
+ __cfq_set_active_queue(cfqd, cfqq);
}

/*
diff --git a/block/cfq.h b/block/cfq.h
index 54a6d90..2a15592 100644
--- a/block/cfq.h
+++ b/block/cfq.h
@@ -16,9 +16,9 @@ static inline void cfq_blkiocg_update_dequeue_stats(struct blkio_group *blkg,
}

static inline void cfq_blkiocg_update_timeslice_used(struct blkio_group *blkg,
- unsigned long time)
+ unsigned long time, unsigned long unaccounted_time)
{
- blkiocg_update_timeslice_used(blkg, time);
+ blkiocg_update_timeslice_used(blkg, time, unaccounted_time);
}

static inline void cfq_blkiocg_set_start_empty_time(struct blkio_group *blkg)
@@ -85,7 +85,7 @@ static inline void cfq_blkiocg_update_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue) {}

static inline void cfq_blkiocg_update_timeslice_used(struct blkio_group *blkg,
- unsigned long time) {}
+ unsigned long time, unsigned long unaccounted_time) {}
static inline void cfq_blkiocg_set_start_empty_time(struct blkio_group *blkg) {}
static inline void cfq_blkiocg_update_io_remove_stats(struct blkio_group *blkg,
bool direction, bool sync) {}
--
1.7.3.1