Messages in this thread | | | From | Andrea Righi <> | Subject | [PATCH v2 0/3] distinct load average per-cpuset | Date | Sat, 20 Oct 2012 21:05:59 +0200 |
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Overview ~~~~~~~~ The cpusets subsystem allows to assign a different set of CPUs to a cgroup. A typical use case is to split large systems in small CPU/memory partitions and isolate certain users/applications in these subsets of the system.
Sometimes, to have a quick overview of the state of each partition, we may be interested to get the load average of the CPUs assigned to a particular cpuset, rather than the global load average of the system.
Proposed solution ~~~~~~~~~~~~~~~~~ The proposal is to add a new file in the cpuset subsystem to report the load average of the CPUs assinged to a particular cpuset cgroup.
Example:
# echo 0-1 > /sys/fs/cgroup/cpuset/foo/cpuset.cpus # echo 2-3 > /sys/fs/cgroup/cpuset/bar/cpuset.cpus
# echo $$ > /sys/fs/cgroup/cpuset/foo/tasks # for i in `seq 4`; do yes > /dev/null & done
... after ~5mins ...
# cat /proc/loadavg /sys/fs/cgroup/cpuset/{foo,bar}/cpuset.loadavg 3.99 2.66 1.24 6/377 2855 3.98 2.64 1.20 0.01 0.02 0.04
In this case we can easily find that the cpuset "foo" is the most busy in the system.
ChangeLog v1->v2: - convert rq->nr_uninterruptible to a percpu variable - fix nr_uninterruptible accounting in the wakeup/sleep paths - use DEFINE_PER_CPU() instead of NR_CPUS arrays - in patch 2/3 add a comment to explain the validity of evaluating the cpuset load average as the sum of the individual per-cpu load averages
[ Thanks to Peter Z. for the review and suggestions of v1 ]
TODO: - report nr_running and nr_threads in cpuset.loadavg, producing the same output as /proc/loadavg; in this way we could do nice things like, for example, "mount --bind cpuset.loadavg /proc/loadavg" in a new mount namespace for a specific user that we want to isolate into a specific cpuset cgroup, etc...
[PATCH v2 1/3] sched: introduce distinct per-cpu load average [PATCH v2 2/3] cpusets: add load avgerage interface [PATCH v2 3/3] cpusets: add documentation of the loadavg file
Documentation/cgroups/cpusets.txt | 1 + include/linux/sched.h | 6 ++ kernel/cpuset.c | 108 +++++++++++++++++++++++++++++++++++ kernel/sched/core.c | 112 +++++++++++++++++++++++++++++++------ kernel/sched/debug.c | 3 +- kernel/sched/sched.h | 8 +-- 6 files changed, 214 insertions(+), 24 deletions(-)
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