Re: [PATCH 1/2] hrtimer: don't add clock-base to active_bases if already present

2014-03-26 Thread Thomas Gleixner 


On Thu, 27 Mar 2014, Viresh Kumar wrote:

> If active_bases already has entry for a particular clock type, then we don't
> need to rewrite it while queuing a hrtimer.
> 
> Signed-off-by: Viresh Kumar 
> ---
> Initially I thought of doing this but then thought better remove active_bases
> completely and so didn't sent this one. Now it might find some place for 
> itself
> :).
> 
>  kernel/hrtimer.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
> index da351ad..acfef5f 100644
> --- a/kernel/hrtimer.c
> +++ b/kernel/hrtimer.c
> @@ -864,8 +864,9 @@ static int enqueue_hrtimer(struct hrtimer *timer,
>  {
>   debug_activate(timer);
>  
> + if (!timerqueue_getnext(>active))
> + base->cpu_base->active_bases |= 1 << base->index;
>   timerqueue_add(>active, >node);
> - base->cpu_base->active_bases |= 1 << base->index;

The conditional is more expensive than actually doing the OR operation
at least on x86 as it results in a branch.

Thanks,

tglx
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[PATCH 1/2] hrtimer: don't add clock-base to active_bases if already present

2014-03-26 Thread Viresh Kumar 
If active_bases already has entry for a particular clock type, then we don't
need to rewrite it while queuing a hrtimer.

Signed-off-by: Viresh Kumar 
---
Initially I thought of doing this but then thought better remove active_bases
completely and so didn't sent this one. Now it might find some place for itself
:).

 kernel/hrtimer.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index da351ad..acfef5f 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -864,8 +864,9 @@ static int enqueue_hrtimer(struct hrtimer *timer,
 {
debug_activate(timer);
 
+   if (!timerqueue_getnext(>active))
+   base->cpu_base->active_bases |= 1 << base->index;
timerqueue_add(>active, >node);
-   base->cpu_base->active_bases |= 1 << base->index;
 
/*
 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
-- 
1.7.12.rc2.18.g61b472e

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[PATCH 1/2] hrtimer: don't add clock-base to active_bases if already present

2014-03-26 Thread Viresh Kumar 
If active_bases already has entry for a particular clock type, then we don't
need to rewrite it while queuing a hrtimer.

Signed-off-by: Viresh Kumar viresh.ku...@linaro.org
---
Initially I thought of doing this but then thought better remove active_bases
completely and so didn't sent this one. Now it might find some place for itself
:).

 kernel/hrtimer.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index da351ad..acfef5f 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -864,8 +864,9 @@ static int enqueue_hrtimer(struct hrtimer *timer,
 {
debug_activate(timer);
 
+   if (!timerqueue_getnext(base-active))
+   base-cpu_base-active_bases |= 1  base-index;
timerqueue_add(base-active, timer-node);
-   base-cpu_base-active_bases |= 1  base-index;
 
/*
 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
-- 
1.7.12.rc2.18.g61b472e

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Re: [PATCH 1/2] hrtimer: don't add clock-base to active_bases if already present

2014-03-26 Thread Thomas Gleixner 


On Thu, 27 Mar 2014, Viresh Kumar wrote:

 If active_bases already has entry for a particular clock type, then we don't
 need to rewrite it while queuing a hrtimer.
 
 Signed-off-by: Viresh Kumar viresh.ku...@linaro.org
 ---
 Initially I thought of doing this but then thought better remove active_bases
 completely and so didn't sent this one. Now it might find some place for 
 itself
 :).
 
  kernel/hrtimer.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)
 
 diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
 index da351ad..acfef5f 100644
 --- a/kernel/hrtimer.c
 +++ b/kernel/hrtimer.c
 @@ -864,8 +864,9 @@ static int enqueue_hrtimer(struct hrtimer *timer,
  {
   debug_activate(timer);
  
 + if (!timerqueue_getnext(base-active))
 + base-cpu_base-active_bases |= 1  base-index;
   timerqueue_add(base-active, timer-node);
 - base-cpu_base-active_bases |= 1  base-index;

The conditional is more expensive than actually doing the OR operation
at least on x86 as it results in a branch.

Thanks,

tglx
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