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Message-ID: <20090626190311.GA1412@elte.hu>
Date: Fri, 26 Jun 2009 21:03:11 +0200
From: Ingo Molnar <mingo@...e.hu>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>
Subject: [GIT PULL] timer fixes
Linus,
Please pull the latest timers-fixes-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git timers-fixes-for-linus
The timer stats performance fix seemed significant (and simple)
enough for a post-rc1 merge as it's enabled in a number of distros
by default - but can leave it out if it's too much.
Thanks,
Ingo
------------------>
Arun R Bharadwaj (1):
timers: Fix timer_migration interface which accepts any number as input
Heiko Carstens (1):
timer stats: Optimize by adding quick check to avoid function calls
include/linux/hrtimer.h | 5 +++++
include/linux/timer.h | 4 ++++
kernel/sysctl.c | 5 ++++-
kernel/time/timer_stats.c | 16 ++++++++--------
kernel/timer.c | 2 ++
5 files changed, 23 insertions(+), 9 deletions(-)
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 7400900..54648e6 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -21,6 +21,7 @@
#include <linux/list.h>
#include <linux/wait.h>
#include <linux/percpu.h>
+#include <linux/timer.h>
struct hrtimer_clock_base;
@@ -447,6 +448,8 @@ extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
{
+ if (likely(!timer->start_pid))
+ return;
timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
timer->function, timer->start_comm, 0);
}
@@ -456,6 +459,8 @@ extern void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer,
static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
{
+ if (likely(!timer_stats_active))
+ return;
__timer_stats_hrtimer_set_start_info(timer, __builtin_return_address(0));
}
diff --git a/include/linux/timer.h b/include/linux/timer.h
index ccf882e..be62ec2 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -190,6 +190,8 @@ extern unsigned long get_next_timer_interrupt(unsigned long now);
*/
#ifdef CONFIG_TIMER_STATS
+extern int timer_stats_active;
+
#define TIMER_STATS_FLAG_DEFERRABLE 0x1
extern void init_timer_stats(void);
@@ -203,6 +205,8 @@ extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
{
+ if (likely(!timer_stats_active))
+ return;
__timer_stats_timer_set_start_info(timer, __builtin_return_address(0));
}
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 62e4ff9..c428ba1 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -335,7 +335,10 @@ static struct ctl_table kern_table[] = {
.data = &sysctl_timer_migration,
.maxlen = sizeof(unsigned int),
.mode = 0644,
- .proc_handler = &proc_dointvec,
+ .proc_handler = &proc_dointvec_minmax,
+ .strategy = &sysctl_intvec,
+ .extra1 = &zero,
+ .extra2 = &one,
},
#endif
{
diff --git a/kernel/time/timer_stats.c b/kernel/time/timer_stats.c
index c994530..4cde8b9 100644
--- a/kernel/time/timer_stats.c
+++ b/kernel/time/timer_stats.c
@@ -96,7 +96,7 @@ static DEFINE_MUTEX(show_mutex);
/*
* Collection status, active/inactive:
*/
-static int __read_mostly active;
+int __read_mostly timer_stats_active;
/*
* Beginning/end timestamps of measurement:
@@ -242,7 +242,7 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
struct entry *entry, input;
unsigned long flags;
- if (likely(!active))
+ if (likely(!timer_stats_active))
return;
lock = &per_cpu(lookup_lock, raw_smp_processor_id());
@@ -254,7 +254,7 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
input.timer_flag = timer_flag;
spin_lock_irqsave(lock, flags);
- if (!active)
+ if (!timer_stats_active)
goto out_unlock;
entry = tstat_lookup(&input, comm);
@@ -290,7 +290,7 @@ static int tstats_show(struct seq_file *m, void *v)
/*
* If still active then calculate up to now:
*/
- if (active)
+ if (timer_stats_active)
time_stop = ktime_get();
time = ktime_sub(time_stop, time_start);
@@ -368,18 +368,18 @@ static ssize_t tstats_write(struct file *file, const char __user *buf,
mutex_lock(&show_mutex);
switch (ctl[0]) {
case '0':
- if (active) {
- active = 0;
+ if (timer_stats_active) {
+ timer_stats_active = 0;
time_stop = ktime_get();
sync_access();
}
break;
case '1':
- if (!active) {
+ if (!timer_stats_active) {
reset_entries();
time_start = ktime_get();
smp_mb();
- active = 1;
+ timer_stats_active = 1;
}
break;
default:
diff --git a/kernel/timer.c b/kernel/timer.c
index 54d3912..0b36b9e 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -380,6 +380,8 @@ static void timer_stats_account_timer(struct timer_list *timer)
{
unsigned int flag = 0;
+ if (likely(!timer->start_site))
+ return;
if (unlikely(tbase_get_deferrable(timer->base)))
flag |= TIMER_STATS_FLAG_DEFERRABLE;
--
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