diff options
Diffstat (limited to 'Documentation/cgroups/blkio-controller.txt')
| -rw-r--r-- | Documentation/cgroups/blkio-controller.txt | 35 |
1 files changed, 15 insertions, 20 deletions
diff --git a/Documentation/cgroups/blkio-controller.txt b/Documentation/cgroups/blkio-controller.txt index d422b410a995..48e0b21b0059 100644 --- a/Documentation/cgroups/blkio-controller.txt +++ b/Documentation/cgroups/blkio-controller.txt @@ -17,6 +17,9 @@ HOWTO You can do a very simple testing of running two dd threads in two different cgroups. Here is what you can do. +- Enable Block IO controller + CONFIG_BLK_CGROUP=y + - Enable group scheduling in CFQ CONFIG_CFQ_GROUP_IOSCHED=y @@ -54,24 +57,16 @@ cgroups. Here is what you can do. Various user visible config options =================================== -CONFIG_CFQ_GROUP_IOSCHED - - Enables group scheduling in CFQ. Currently only 1 level of group - creation is allowed. - -CONFIG_DEBUG_CFQ_IOSCHED - - Enables some debugging messages in blktrace. Also creates extra - cgroup file blkio.dequeue. - -Config options selected automatically -===================================== -These config options are not user visible and are selected/deselected -automatically based on IO scheduler configuration. - CONFIG_BLK_CGROUP - - Block IO controller. Selected by CONFIG_CFQ_GROUP_IOSCHED. + - Block IO controller. CONFIG_DEBUG_BLK_CGROUP - - Debug help. Selected by CONFIG_DEBUG_CFQ_IOSCHED. + - Debug help. Right now some additional stats file show up in cgroup + if this option is enabled. + +CONFIG_CFQ_GROUP_IOSCHED + - Enables group scheduling in CFQ. Currently only 1 level of group + creation is allowed. Details of cgroup files ======================= @@ -174,13 +169,13 @@ Details of cgroup files write, sync or async. - blkio.avg_queue_size - - Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y. + - Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y. The average queue size for this cgroup over the entire time of this 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. + - Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=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 @@ -191,7 +186,7 @@ Details of cgroup files got a timeslice and will not include the current delta. - blkio.empty_time - - Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y. + - Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=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 @@ -200,7 +195,7 @@ Details of cgroup files 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. + - Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=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 @@ -209,7 +204,7 @@ Details of cgroup files the current delta. - blkio.dequeue - - Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y. This + - Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y. This gives the statistics about how many a times a group was dequeued from service tree of the device. First two fields specify the major and minor number of the device and third field specifies the number |