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authorMike Galbraith <mgalbraith@suse.de>2011-11-22 09:20:07 -0500
committerIngo Molnar <mingo@elte.hu>2011-12-06 14:51:20 -0500
commitb39e66eaf9c573f38133e894256caeaf9fd2a528 (patch)
tree316e239a62d589515bbe4c4b9b8c4fc8cac91715 /kernel/sched
parentfdaabd800bdd60652a448994eeb77442180db6c0 (diff)
sched: Save some hrtick_start_fair cycles
hrtick_start_fair() shows up in profiles even when disabled. v3.0.6 taskset -c 3 pipe-test PerfTop: 997 irqs/sec kernel:89.5% exact: 0.0% [1000Hz cycles], (all, CPU: 3) ------------------------------------------------------------------------------------------------ Virgin Patched samples pcnt function samples pcnt function _______ _____ ___________________________ _______ _____ ___________________________ 2880.00 10.2% __schedule 3136.00 11.3% __schedule 1634.00 5.8% pipe_read 1615.00 5.8% pipe_read 1458.00 5.2% system_call 1534.00 5.5% system_call 1382.00 4.9% _raw_spin_lock_irqsave 1412.00 5.1% _raw_spin_lock_irqsave 1202.00 4.3% pipe_write 1255.00 4.5% copy_user_generic_string 1164.00 4.1% copy_user_generic_string 1241.00 4.5% __switch_to 1097.00 3.9% __switch_to 929.00 3.3% mutex_lock 872.00 3.1% mutex_lock 846.00 3.0% mutex_unlock 687.00 2.4% mutex_unlock 804.00 2.9% pipe_write 682.00 2.4% native_sched_clock 713.00 2.6% native_sched_clock 643.00 2.3% system_call_after_swapgs 653.00 2.3% _raw_spin_unlock_irqrestore 617.00 2.2% sched_clock_local 633.00 2.3% fsnotify 612.00 2.2% fsnotify 605.00 2.2% sched_clock_local 596.00 2.1% _raw_spin_unlock_irqrestore 593.00 2.1% system_call_after_swapgs 542.00 1.9% sysret_check 559.00 2.0% sysret_check 467.00 1.7% fget_light 472.00 1.7% fget_light 462.00 1.6% finish_task_switch 461.00 1.7% finish_task_switch 437.00 1.5% vfs_write 442.00 1.6% vfs_write 431.00 1.5% do_sync_write 428.00 1.5% do_sync_write 413.00 1.5% select_task_rq_fair 404.00 1.5% _raw_spin_lock_irq 386.00 1.4% update_curr 402.00 1.4% update_curr 385.00 1.4% rw_verify_area 389.00 1.4% do_sync_read 377.00 1.3% _raw_spin_lock_irq 378.00 1.4% vfs_read 369.00 1.3% do_sync_read 340.00 1.2% pipe_iov_copy_from_user 360.00 1.3% vfs_read 316.00 1.1% __wake_up_sync_key * 342.00 1.2% hrtick_start_fair 313.00 1.1% __wake_up_common Signed-off-by: Mike Galbraith <efault@gmx.de> [ fixed !CONFIG_SCHED_HRTICK borkage ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1321971607.6855.17.camel@marge.simson.net Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/fair.c7
-rw-r--r--kernel/sched/sched.h7
2 files changed, 11 insertions, 3 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 65a6f8b1bf14..4174338ffa36 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2137,7 +2137,7 @@ static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
2137 2137
2138 WARN_ON(task_rq(p) != rq); 2138 WARN_ON(task_rq(p) != rq);
2139 2139
2140 if (hrtick_enabled(rq) && cfs_rq->nr_running > 1) { 2140 if (cfs_rq->nr_running > 1) {
2141 u64 slice = sched_slice(cfs_rq, se); 2141 u64 slice = sched_slice(cfs_rq, se);
2142 u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime; 2142 u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime;
2143 s64 delta = slice - ran; 2143 s64 delta = slice - ran;
@@ -2168,7 +2168,7 @@ static void hrtick_update(struct rq *rq)
2168{ 2168{
2169 struct task_struct *curr = rq->curr; 2169 struct task_struct *curr = rq->curr;
2170 2170
2171 if (curr->sched_class != &fair_sched_class) 2171 if (!hrtick_enabled(rq) || curr->sched_class != &fair_sched_class)
2172 return; 2172 return;
2173 2173
2174 if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency) 2174 if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency)
@@ -3031,7 +3031,8 @@ static struct task_struct *pick_next_task_fair(struct rq *rq)
3031 } while (cfs_rq); 3031 } while (cfs_rq);
3032 3032
3033 p = task_of(se); 3033 p = task_of(se);
3034 hrtick_start_fair(rq, p); 3034 if (hrtick_enabled(rq))
3035 hrtick_start_fair(rq, p);
3035 3036
3036 return p; 3037 return p;
3037} 3038}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 91810f0ee3af..d88545c667e3 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -885,6 +885,13 @@ static inline int hrtick_enabled(struct rq *rq)
885 885
886void hrtick_start(struct rq *rq, u64 delay); 886void hrtick_start(struct rq *rq, u64 delay);
887 887
888#else
889
890static inline int hrtick_enabled(struct rq *rq)
891{
892 return 0;
893}
894
888#endif /* CONFIG_SCHED_HRTICK */ 895#endif /* CONFIG_SCHED_HRTICK */
889 896
890#ifdef CONFIG_SMP 897#ifdef CONFIG_SMP