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| author | Yuyang Du <yuyang.du@intel.com> | 2016-04-05 04:12:26 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-05-05 07:24:00 (GMT) |
| commit | 6ecdd74962f246dfe8750b7bea481a1c0816315d (patch) | |
| tree | 3b07aefd3f08af08e983771f34eb1f9037cc7848 /kernel/sched/fair.c | |
| parent | 2159197d66770ec01f75c93fb11dc66df81fd45b (diff) | |
| download | linux-6ecdd74962f246dfe8750b7bea481a1c0816315d.tar.xz | |
sched/fair: Generalize the load/util averages resolution definition
Integer metric needs fixed point arithmetic. In sched/fair, a few
metrics, e.g., weight, load, load_avg, util_avg, freq, and capacity,
may have different fixed point ranges, which makes their update and
usage error-prone.
In order to avoid the errors relating to the fixed point range, we
definie a basic fixed point range, and then formalize all metrics to
base on the basic range.
The basic range is 1024 or (1 << 10). Further, one can recursively
apply the basic range to have larger range.
Pointed out by Ben Segall, weight (visible to user, e.g., NICE-0 has
1024) and load (e.g., NICE_0_LOAD) have independent ranges, but they
must be well calibrated.
Signed-off-by: Yuyang Du <yuyang.du@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bsegall@google.com
Cc: dietmar.eggemann@arm.com
Cc: lizefan@huawei.com
Cc: morten.rasmussen@arm.com
Cc: pjt@google.com
Cc: umgwanakikbuti@gmail.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1459829551-21625-2-git-send-email-yuyang.du@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 91395e1..76ca86e 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2662,10 +2662,6 @@ static u32 __compute_runnable_contrib(u64 n) return contrib + runnable_avg_yN_sum[n]; } -#if (SCHED_LOAD_SHIFT - SCHED_LOAD_RESOLUTION) != 10 || SCHED_CAPACITY_SHIFT != 10 -#error "load tracking assumes 2^10 as unit" -#endif - #define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT) /* |