[PATCH] Make clocksource insert entry more efficiently

[PATCH] Make clocksource insert entry more efficiently

[Minfei Huang]

It is unnecessary to continue looping the list, if we find there is an
entry that the value of rating is smaller than the new one. It is safe
to be out the loop, because all of entry are inserted in descending
order.

Signed-off-by: Minfei Huang <mnghuan@gmail.com>
---
 kernel/time/clocksource.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 56ece14..6a5a310 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -669,10 +669,12 @@ static void clocksource_enqueue(struct clocksource *cs)
 	struct list_head *entry = &clocksource_list;
 	struct clocksource *tmp;
 
-	list_for_each_entry(tmp, &clocksource_list, list)
+	list_for_each_entry(tmp, &clocksource_list, list) {
 		/* Keep track of the place, where to insert */
-		if (tmp->rating >= cs->rating)
-			entry = &tmp->list;
+		if (tmp->rating < cs->rating)
+			break;
+		entry = &tmp->list;
+	}
 	list_add(&cs->list, entry);
 }
 
-- 
2.6.3

Re: [PATCH] Make clocksource insert entry more efficiently

[Minfei Huang]

Ping.

Any comment is appreciate.

Thanks
Minfei

On 04/25/16 at 05:20P, Minfei Huang wrote:
> It is unnecessary to continue looping the list, if we find there is an
> entry that the value of rating is smaller than the new one. It is safe
> to be out the loop, because all of entry are inserted in descending
> order.
> 
> Signed-off-by: Minfei Huang <mnghuan@gmail.com>
> ---
>  kernel/time/clocksource.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
> index 56ece14..6a5a310 100644
> --- a/kernel/time/clocksource.c
> +++ b/kernel/time/clocksource.c
> @@ -669,10 +669,12 @@ static void clocksource_enqueue(struct clocksource *cs)
>  	struct list_head *entry = &clocksource_list;
>  	struct clocksource *tmp;
>  
> -	list_for_each_entry(tmp, &clocksource_list, list)
> +	list_for_each_entry(tmp, &clocksource_list, list) {
>  		/* Keep track of the place, where to insert */
> -		if (tmp->rating >= cs->rating)
> -			entry = &tmp->list;
> +		if (tmp->rating < cs->rating)
> +			break;
> +		entry = &tmp->list;
> +	}
>  	list_add(&cs->list, entry);
>  }
>  
> -- 
> 2.6.3
> 

Re: [PATCH] Make clocksource insert entry more efficiently

[John Stultz]

On Mon, Apr 25, 2016 at 2:20 AM, Minfei Huang <mnghuan@gmail.com> wrote:
> It is unnecessary to continue looping the list, if we find there is an
> entry that the value of rating is smaller than the new one. It is safe
> to be out the loop, because all of entry are inserted in descending
> order.
>
> Signed-off-by: Minfei Huang <mnghuan@gmail.com>
> ---

Thanks for sending this in. It looks reasonable to me, though not
likely to gain a ton, as these are usually short lists, and we only
really tinker with them at bootup. But yea. I'll put it on my toqueue
list for testing.

Its maybe a little close to make it for 4.7, but we'll see.

Thanks again!
-john

Re: [PATCH] Make clocksource insert entry more efficiently

[Minfei Huang]

On 05/02/16 at 10:39P, John Stultz wrote:
> On Mon, Apr 25, 2016 at 2:20 AM, Minfei Huang <mnghuan@gmail.com> wrote:
> > It is unnecessary to continue looping the list, if we find there is an
> > entry that the value of rating is smaller than the new one. It is safe
> > to be out the loop, because all of entry are inserted in descending
> > order.
> >
> > Signed-off-by: Minfei Huang <mnghuan@gmail.com>
> > ---
> 
> Thanks for sending this in. It looks reasonable to me, though not
> likely to gain a ton, as these are usually short lists, and we only
> really tinker with them at bootup. But yea. I'll put it on my toqueue
> list for testing.
> 
> Its maybe a little close to make it for 4.7, but we'll see.
> 
> Thanks again!
> -john

Thanks

Minfei