diff options
| author | Viresh Kumar <viresh.kumar@linaro.org> | 2015-03-25 12:50:53 +0530 |
|---|---|---|
| committer | Gary S. Robertson <gary.robertson@linaro.org> | 2015-07-22 16:06:19 -0500 |
| commit | b2dfa6c8d6b61300f0dbafca3ea588bae6ef2f68 (patch) | |
| tree | e8068c3fa2ed058fdf147c904e429006c9ea3320 /Documentation | |
| parent | 8451e6b7dc1ab521169bd9649dbdfd3684c80ce3 (diff) | |
cpuset: Create sysfs file: cpusets.quiesce to isolate CPUs
For networking applications, platforms need to provide one CPU per each user
space data plane thread. These CPUs shouldn't be interrupted by kernel at all
unless userspace has requested for some functionality. Currently, there are
background kernel activities that are running on almost every CPU, like:
timers/hrtimers/watchdogs/etc, and these are required to be migrated to other
CPUs.
To achieve that, this patch adds another option to cpusets, i.e. 'quiesce'.
Writing '1' on this file would migrate these unbound/unpinned timers/hrtimers
away from the CPUs of the cpuset in question. Also it would disallow addition of
any new unpinned timers/hrtimers to isolated CPUs (This would be handled in next
patch). Writing '0' will disable isolation of CPUs in current cpuset and
unpinned timers/hrtimers would be allowed in future on these CPUs.
Currently, only timers and hrtimers are migrated. This would be followed by
other kernel infrastructure later if required.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[forward port to 3.18]
Signed-off-by: Santosh Shukla <santosh.shukla@linaro.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/cgroups/cpusets.txt | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/Documentation/cgroups/cpusets.txt b/Documentation/cgroups/cpusets.txt index 3c94ff3f9693..b7723632f502 100644 --- a/Documentation/cgroups/cpusets.txt +++ b/Documentation/cgroups/cpusets.txt @@ -22,7 +22,8 @@ CONTENTS: 1.6 What is memory spread ? 1.7 What is sched_load_balance ? 1.8 What is sched_relax_domain_level ? - 1.9 How do I use cpusets ? + 1.9 What is quiesce? + 1.10 How do I use cpusets ? 2. Usage Examples and Syntax 2.1 Basic Usage 2.2 Adding/removing cpus @@ -581,7 +582,21 @@ If your situation is: then increasing 'sched_relax_domain_level' would benefit you. -1.9 How do I use cpusets ? +1.9 What is quiesce ? +-------------------------------------- +We need to migrate away all the background kernel activities (Unbound) for +systems requiring isolation of cores (HPC, Real time, networking, etc). After +creating cpusets, you can write 1 or 0 to cpuset.quiesce file. + +Writing '1': on this file would migrate unbound/unpinned timers and hrtimers +away from the CPUs of the cpuset in question. Also it would disallow addition of +any new unpinned timers & hrtimers to isolated CPUs. + +Writing '0': will disable isolation of CPUs in current cpuset and unpinned +timers/hrtimers would be allowed in future on these CPUs. + + +1.10 How do I use cpusets ? -------------------------- In order to minimize the impact of cpusets on critical kernel |