lkml.org 
[lkml]   [2022]   [Aug]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
SubjectRe: [PATCH v2 09/10] sched/psi: per-cgroup PSI stats disable/re-enable interface
From
On 2022/8/12 18:14, Michal Koutný wrote:
> Hello Chengming.
>
> On Mon, Aug 08, 2022 at 07:03:40PM +0800, Chengming Zhou <zhouchengming@bytedance.com> wrote:
>> diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
>> index dd84e34bc051..ade40506ab80 100644
>> --- a/Documentation/admin-guide/cgroup-v2.rst
>> +++ b/Documentation/admin-guide/cgroup-v2.rst
>> @@ -968,6 +968,13 @@ All cgroup core files are prefixed with "cgroup."
>> killing cgroups is a process directed operation, i.e. it affects
>> the whole thread-group.
>>
>> + cgroup.psi
>> + A read-write single value file that allowed values are "0" and "1".
>> + The default is "1".
>> +
>> + Writing "0" to the file will disable the cgroup PSI stats accounting.
>> + Writing "1" to the file will re-enable the cgroup PSI stats accounting.
>> +
>
> I'd suggest explaining here explicitely, this control attribute is not
> hierarchical (i.e. PSI accounting in a cgroup does not affect accounting
> in descendants and doesn't need pass enablement via ancestors from
> root). And the purpose that it "saves" cycles (where).

Thanks for the suggestion and explanation!

Could you help take a look if there is anything to improve?


--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -968,6 +968,23 @@ All cgroup core files are prefixed with "cgroup."
killing cgroups is a process directed operation, i.e. it affects
the whole thread-group.

+ cgroup.pressure
+ A read-write single value file that allowed values are "0" and "1".
+ The default is "1".
+
+ Writing "0" to the file will disable the cgroup PSI accounting.
+ Writing "1" to the file will re-enable the cgroup PSI accounting.
+
+ This control attribute is not hierarchical, so disable or enable PSI
+ accounting in a cgroup does not affect PSI accounting in descendants
+ and doesn't need pass enablement via ancestors from root.
+
+ The reason this control attribute exists is that PSI accounts stalls for
+ each cgroup separately and aggregates it at each level of the hierarchy.
+ This may cause non-negligible overhead for some workloads when under
+ deep level of the hierarchy, in which case this control attribute can
+ be used to disable PSI accounting in the cgroups.
+

\
 
 \ /
  Last update: 2022-08-12 14:38    [W:0.120 / U:3.072 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site