Messages in this thread | | | Date | Mon, 26 Aug 2013 10:56:39 +0800 | Subject | Re: [PATCH 03/10] sched: Clean-up struct sd_lb_stat | From | Lei Wen <> |
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On Tue, Aug 20, 2013 at 12:01 AM, Peter Zijlstra <peterz@infradead.org> wrote: > From: Joonsoo Kim <iamjoonsoo.kim@lge.com> > > There is no reason to maintain separate variables for this_group > and busiest_group in sd_lb_stat, except saving some space. > But this structure is always allocated in stack, so this saving > isn't really benificial [peterz: reducing stack space is good; in this > case readability increases enough that I think its still beneficial] > > This patch unify these variables, so IMO, readability may be improved. > > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> > [peterz: lots of style edits, a few fixes and a rename] > Signed-off-by: Peter Zijlstra <peterz@infradead.org> > Link: http://lkml.kernel.org/r/1375778203-31343-4-git-send-email-iamjoonsoo.kim@lge.com > --- > kernel/sched/fair.c | 225 +++++++++++++++++++++++++--------------------------- > 1 file changed, 112 insertions(+), 113 deletions(-) > > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -4277,36 +4277,6 @@ static unsigned long task_h_load(struct > [snip]... > - env->imbalance = DIV_ROUND_CLOSEST( > - sds->max_load * sds->busiest->sgp->power, SCHED_POWER_SCALE); > + env->imbalance = DIV_ROUND_CLOSEST(sds->busiest_stat.avg_load * > + sds->busiest->sgp->power, SCHED_POWER_SCALE); >
I am wondering whether we could change this line as below is more appropriate, since it would avoid the division here: env->imbalance = (sds->busiest_stat.avg_load * sds->busiest->sgp->power) >> SCHED_POWER_SHIFT;
I am not sure whether compiler would be smarter enough to covert into >> operation, if it see SCHED_POWER_SCALE is 1024 here.
Thanks, Lei
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