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| author | Peter Zijlstra <peterz@infradead.org> | 2016-04-28 12:49:38 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-05-05 09:24:00 +0200 |
| commit | 2159197d66770ec01f75c93fb11dc66df81fd45b (patch) | |
| tree | f9e1aefa2e9ca89f8daae7c31c0975d43c39ad09 /kernel/sched/sched.h | |
| parent | e7904a28f5331c21d17af638cb477c83662e3cb6 (diff) | |
| download | op-kernel-dev-2159197d66770ec01f75c93fb11dc66df81fd45b.zip op-kernel-dev-2159197d66770ec01f75c93fb11dc66df81fd45b.tar.gz | |
sched/core: Enable increased load resolution on 64-bit kernels
Mike ran into the low load resolution limitation on his big machine.
So reenable these bits; nobody could ever reproduce/analyze the
reported power usage claim and Google has been running with this for
years as well.
Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Tested-by: Mike Galbraith <umgwanakikbuti@gmail.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: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/sched.h')
| -rw-r--r-- | kernel/sched/sched.h | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 0b6a838..066a4c2 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -49,11 +49,13 @@ static inline void cpu_load_update_active(struct rq *this_rq) { } * and does not change the user-interface for setting shares/weights. * * We increase resolution only if we have enough bits to allow this increased - * resolution (i.e. BITS_PER_LONG > 32). The costs for increasing resolution - * when BITS_PER_LONG <= 32 are pretty high and the returns do not justify the - * increased costs. + * resolution (i.e. 64bit). The costs for increasing resolution when 32bit are + * pretty high and the returns do not justify the increased costs. + * + * Really only required when CONFIG_FAIR_GROUP_SCHED is also set, but to + * increase coverage and consistency always enable it on 64bit platforms. */ -#if 0 /* BITS_PER_LONG > 32 -- currently broken: it increases power usage under light load */ +#ifdef CONFIG_64BIT # define SCHED_LOAD_RESOLUTION 10 # define scale_load(w) ((w) << SCHED_LOAD_RESOLUTION) # define scale_load_down(w) ((w) >> SCHED_LOAD_RESOLUTION) |
