Messages in this thread | | | Subject | Re: [PATCH] sched: Accelerate "pick_next_entity" under special condition | From | Peter Zijlstra <> | Date | Mon, 16 Jan 2012 10:51:43 +0100 |
| |
On Mon, 2012-01-16 at 17:37 +0800, Michael Wang wrote: > From: Michael Wang <wangyun@linux.vnet.ibm.com> > > We can avoid some useless operation in some special condition.
This is a pretty empty statement.
> For example: > If we have "cfs_rq->next" and it can be use, we just return it directly.
What it doesn't state is what it actually does, if it affects the common case and performance numbers (or a good reason for the lack thereof).
> Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com> > --- > kernel/sched/fair.c | 28 +++++++++++++++++----------- > 1 files changed, 17 insertions(+), 11 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 84adb2d..9fc2c3c 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -1295,6 +1295,8 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) > static int > wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se); > > +#define ENTITY_PREEMPT_ALLOWED(prev,next) (wakeup_preempt_entity(prev, next) < 1)
This is just uglification imo, its shouting and it doesn't actually win you much space.
| |