lkml.org 
[lkml]   [2022]   [Jun]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH] sched/pelt: Fix bracket typo
On Wed, 8 Jun 2022 at 18:30, 龍帆軒 <1030steven@gmail.com> wrote:
>
>
> Randy Dunlap <rdunlap@infradead.org> 於 2022年6月8日 下午11:33 寫道:
>
>
>
> On 6/8/22 08:00, Steven Lung wrote:
>
> The second bracket describing the range is inverted, this patch
> will fix it.
>
> Signed-off-by: Steven Lung <1030steven@gmail.com>
> ---
> kernel/sched/pelt.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
> index 0f3107682..ed82cfba9 100644
> --- a/kernel/sched/pelt.c
> +++ b/kernel/sched/pelt.c
> @@ -233,7 +233,7 @@ ___update_load_sum(u64 now, struct sched_avg *sa,
> * When syncing *_avg with *_sum, we must take into account the current
> * position in the PELT segment otherwise the remaining part of the segment
> * will be considered as idle time whereas it's not yet elapsed and this will
> - * generate unwanted oscillation in the range [1002..1024[.
>
>
> Is the above the same as range [1002..1024).
> ? I.e. 1002-1023 inclusive (or 1024 excluded)?

yes, 1024 was excluded from the range because we reached 1024 when
period_contrib == 1024 but when period_contrib == 1024 we decayed and
period_contrib becomes 0 and the load_avg went down to 1002.

Before the changes, the load_avg for default weight was
1024*(LOAD_AVG_MAX-1024+period_contrib)/LOAD_AVG_MAX
if period_contrib == 0 ie the beg of the window we've got a load_avg of 1002
if period_contrib == 1023 ie the end of the window we've got a load of
int(1023.97)==1023

In French, we use [1002..1024[ but english version is [1002..1024)

>
> + * generate unwanted oscillation in the range [1002..1024].
> *
> * The max value of *_sum varies with the position in the time segment and is
> * equals to :
>
>
> --
> ~Randy
>
>
> In the patch that the author submitted[1] for this comment, he mentioned that the value 1024 can be obtained.
> So I think we should use brackets instead of parenthesis.
>
> [1]: https://lore.kernel.org/all/20200506155301.14288-1-vincent.guittot@linaro.org/T/#u
>
> --
> Steven
>

\
 
 \ /
  Last update: 2022-09-17 16:25    [W:2.267 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site