diff options
Diffstat (limited to 'Documentation/cgroups')
| -rw-r--r-- | Documentation/cgroups/blkio-controller.txt | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/Documentation/cgroups/blkio-controller.txt b/Documentation/cgroups/blkio-controller.txt index 6e52e7c512a..db054ea3e7f 100644 --- a/Documentation/cgroups/blkio-controller.txt +++ b/Documentation/cgroups/blkio-controller.txt @@ -150,6 +150,35 @@ Details of cgroup files cgroup's existence. Queue size samples are taken each time one of the queues of this cgroup gets a timeslice. +- blkio.group_wait_time + - Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y. + This is the amount of time the cgroup had to wait since it became busy + (i.e., went from 0 to 1 request queued) to get a timeslice for one of + its queues. 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 is in nanoseconds. If this is + read when the cgroup is in a waiting (for timeslice) state, the stat + will only report the group_wait_time accumulated till the last time it + got a timeslice and will not include the current delta. + +- blkio.empty_time + - Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y. + This is the amount of time a cgroup spends without any pending + requests when not being served, i.e., it does not include any time + spent idling for one of the queues of the cgroup. This is in + nanoseconds. If this is read when the cgroup is in an empty state, + the stat will only report the empty_time accumulated till the last + time it had a pending request and will not include the current delta. + +- blkio.idle_time + - Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y. + 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. This is in nanoseconds. If this is read + when the cgroup is in an idling state, the stat will only report the + idle_time accumulated till the last idle period and will not include + the current delta. + - blkio.dequeue - Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y. This gives the statistics about how many a times a group was dequeued |