diff options
author | Jiri Kosina <jkosina@suse.cz> | 2011-05-18 17:06:31 +0200 |
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committer | Jiri Kosina <jkosina@suse.cz> | 2011-05-18 17:06:49 +0200 |
commit | 6b7b8e488bbdedeccabdd001a78ffcbe43bb8a3a (patch) | |
tree | f2f77cc31b4548745778fca6a51b09e1d8a49804 /Documentation/cgroups/blkio-controller.txt | |
parent | b50f315cbb865079a16a12fd9ae6083f98fd592c (diff) | |
parent | c1d10d18c542278b7fbc413c289d3cb6219da6b3 (diff) |
Merge branch 'master' into upstream.
This is sync with Linus' tree to receive KEY_IMAGES definition
that went in through input tree.
Diffstat (limited to 'Documentation/cgroups/blkio-controller.txt')
-rw-r--r-- | Documentation/cgroups/blkio-controller.txt | 30 |
1 files changed, 1 insertions, 29 deletions
diff --git a/Documentation/cgroups/blkio-controller.txt b/Documentation/cgroups/blkio-controller.txt index 4ed7b5ceeed..465351d4cf8 100644 --- a/Documentation/cgroups/blkio-controller.txt +++ b/Documentation/cgroups/blkio-controller.txt @@ -140,7 +140,7 @@ Proportional weight policy files - Specifies per cgroup weight. This is default weight of the group on all the devices until and unless overridden by per device rule. (See blkio.weight_device). - Currently allowed range of weights is from 100 to 1000. + Currently allowed range of weights is from 10 to 1000. - blkio.weight_device - One can specify per cgroup per device rules using this interface. @@ -343,34 +343,6 @@ Common files among various policies CFQ sysfs tunable ================= -/sys/block/<disk>/queue/iosched/group_isolation ------------------------------------------------ - -If group_isolation=1, it provides stronger isolation between groups at the -expense of throughput. By default group_isolation is 0. In general that -means that if group_isolation=0, expect fairness for sequential workload -only. Set group_isolation=1 to see fairness for random IO workload also. - -Generally CFQ will put random seeky workload in sync-noidle category. CFQ -will disable idling on these queues and it does a collective idling on group -of such queues. Generally these are slow moving queues and if there is a -sync-noidle service tree in each group, that group gets exclusive access to -disk for certain period. That means it will bring the throughput down if -group does not have enough IO to drive deeper queue depths and utilize disk -capacity to the fullest in the slice allocated to it. But the flip side is -that even a random reader should get better latencies and overall throughput -if there are lots of sequential readers/sync-idle workload running in the -system. - -If group_isolation=0, then CFQ automatically moves all the random seeky queues -in the root group. That means there will be no service differentiation for -that kind of workload. This leads to better throughput as we do collective -idling on root sync-noidle tree. - -By default one should run with group_isolation=0. If that is not sufficient -and one wants stronger isolation between groups, then set group_isolation=1 -but this will come at cost of reduced throughput. - /sys/block/<disk>/queue/iosched/slice_idle ------------------------------------------ On a faster hardware CFQ can be slow, especially with sequential workload. |