Messages in this thread Patch in this message | | | Subject | Re: [PATCH 01/18] move do_timer() from kernel/timer.c into kernel/time/timekeeping.c | From | Peter Zijlstra <> | Date | Tue, 25 Jan 2011 11:34:37 +0100 |
| |
On Tue, 2011-01-25 at 10:08 +0100, Peter Zijlstra wrote: > On Mon, 2011-01-24 at 23:44 +0100, Thomas Gleixner wrote: > > On Mon, 24 Jan 2011, Peter Zijlstra wrote: > > > > > On Mon, 2011-01-24 at 23:10 +0100, Thomas Gleixner wrote: > > > > The call to calc_global_load() is there for hysterical raisins and we > > > > really should get rid of it sooner than later. I'm quite sure that it > > > > could be run from a timer callback as well. Peter ? > > > > > > calc_global_load() wants to be called on just one cpu, do we have a > > > better place for that? > > > > Well, we can call it from a timer from a single CPU. > > Right that would work I guess.
Something like the (completely untested) below would do I guess:
--- Subject: sched: Move the calc_global_load() call into the scheduler From: Peter Zijlstra <a.p.zijlstra@chello.nl> Date: Tue Jan 25 11:30:35 CET 2011
Remove the calc_global_load() call from the timekeeping code and make it local to the scheduler.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> --- include/linux/sched.h | 2 -- kernel/sched.c | 22 ++++++++++++++++------ kernel/timer.c | 1 - 3 files changed, 16 insertions(+), 9 deletions(-)
Index: linux-2.6/include/linux/sched.h =================================================================== --- linux-2.6.orig/include/linux/sched.h +++ linux-2.6/include/linux/sched.h @@ -142,8 +142,6 @@ extern unsigned long nr_iowait_cpu(int c extern unsigned long this_cpu_load(void); -extern void calc_global_load(unsigned long ticks); - extern unsigned long get_parent_ip(unsigned long addr); struct seq_file; Index: linux-2.6/kernel/sched.c =================================================================== --- linux-2.6.orig/kernel/sched.c +++ linux-2.6/kernel/sched.c @@ -3192,7 +3192,7 @@ calc_load_n(unsigned long load, unsigned * Once we've updated the global active value, we need to apply the exponential * weights adjusted to the number of cycles missed. */ -static void calc_global_nohz(unsigned long ticks) +static void calc_global_nohz(void) { long delta, active, n; @@ -3209,11 +3209,13 @@ static void calc_global_nohz(unsigned lo if (delta) atomic_long_add(delta, &calc_load_tasks); + /* * If we were idle for multiple load cycles, apply them. */ - if (ticks >= LOAD_FREQ) { - n = ticks / LOAD_FREQ; + delta = jiffies - calc_load_update - 10; + if (delta >= LOAD_FREQ) { + n = delta / LOAD_FREQ; active = atomic_long_read(&calc_load_tasks); active = active > 0 ? active * FIXED_1 : 0; @@ -3246,7 +3248,7 @@ static inline long calc_load_fold_idle(v return 0; } -static void calc_global_nohz(unsigned long ticks) +static void calc_global_nohz(void) { } #endif @@ -3266,15 +3268,20 @@ void get_avenrun(unsigned long *loads, u loads[2] = (avenrun[2] + offset) << shift; } +static void calc_global_load(unsigned long __data); + +static struct timer_list global_load_timer = + TIMER_DEFERRED_INITIALIZER(calc_global_load, 0, 0); + /* * calc_load - update the avenrun load estimates 10 ticks after the * CPUs have updated calc_load_tasks. */ -void calc_global_load(unsigned long ticks) +static void calc_global_load(unsigned long __data) { long active; - calc_global_nohz(ticks); + calc_global_nohz(); if (time_before(jiffies, calc_load_update + 10)) return; @@ -3287,6 +3294,7 @@ void calc_global_load(unsigned long tick avenrun[2] = calc_load(avenrun[2], EXP_15, active); calc_load_update += LOAD_FREQ; + mod_timer(&global_load_timer, calc_load_update + 10); } /* @@ -8172,6 +8180,8 @@ void __init sched_init(void) init_idle(current, smp_processor_id()); calc_load_update = jiffies + LOAD_FREQ; + global_load_timer.slack = 0; + mod_timer(&global_load_timer, calc_load_update + 10); /* * During early bootup we pretend to be a normal task: Index: linux-2.6/kernel/timer.c =================================================================== --- linux-2.6.orig/kernel/timer.c +++ linux-2.6/kernel/timer.c @@ -1303,7 +1303,6 @@ void do_timer(unsigned long ticks) { jiffies_64 += ticks; update_wall_time(); - calc_global_load(ticks); } #ifdef __ARCH_WANT_SYS_ALARM
| |