Messages in this thread | | | From | Vincent Guittot <> | Date | Wed, 8 Jun 2022 22:14:06 +0200 | Subject | Re: [PATCH] sched/pelt: Fix bracket typo |
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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 >
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