[PATCH] PKT_SCHED: Make rate estimator work for all platforms

[PATCH] PKT_SCHED: Make rate estimator work for all platforms

[Thomas Graf]

Fixes the existing rate estimator to compile cleanly on all platforms
and avoids carrying on the variance on platforms with HZ%4 != 0.

Patch also applies to 2.4 with some fuzz.

Signed-off-by: Thomas Graf <tgraf@suug.ch>

--- linux-2.6.9-rc3-bk4.orig/net/sched/estimator.c	2004-10-04 22:41:26.000000000 +0200
+++ linux-2.6.9-rc3-bk4/net/sched/estimator.c	2004-10-04 22:53:54.000000000 +0200
@@ -66,15 +66,11 @@
 
    * Minimal interval is HZ/4=250msec (it is the greatest common divisor
      for HZ=100 and HZ=1024 8)), maximal interval
-     is (HZ/4)*2^EST_MAX_INTERVAL = 8sec. Shorter intervals
+     is (HZ*2^EST_MAX_INTERVAL)/4 = 8sec. Shorter intervals
      are too expensive, longer ones can be implemented
      at user level painlessly.
  */
 
-#if (HZ%4) != 0
-#error Bad HZ value.
-#endif
-
 #define EST_MAX_INTERVAL	5
 
 struct qdisc_estimator
@@ -128,7 +124,7 @@
 		spin_unlock(e->stats_lock);
 	}
 
-	mod_timer(&elist[idx].timer, jiffies + ((HZ/4)<<idx));
+	mod_timer(&elist[idx].timer, jiffies + ((HZ<<idx)/4));
 	read_unlock(&est_lock);
 }
 
@@ -161,7 +157,7 @@
 	if (est->next == NULL) {
 		init_timer(&elist[est->interval].timer);
 		elist[est->interval].timer.data = est->interval;
-		elist[est->interval].timer.expires = jiffies + ((HZ/4)<<est->interval);
+		elist[est->interval].timer.expires = jiffies + ((HZ<<est->interval)/4);
 		elist[est->interval].timer.function = est_timer;
 		add_timer(&elist[est->interval].timer);
 	}

Re: [PATCH] PKT_SCHED: Make rate estimator work for all platforms

[jamal]

Looking good.
Dave, Please apply all the patches (earlier 3 + this one) that Thomas
posted.

cheers,
jamal

On Mon, 2004-10-04 at 17:11, Thomas Graf wrote:
> Fixes the existing rate estimator to compile cleanly on all platforms
> and avoids carrying on the variance on platforms with HZ%4 != 0.
> 
> Patch also applies to 2.4 with some fuzz.
> 
> Signed-off-by: Thomas Graf <tgraf@suug.ch>
> 
> --- linux-2.6.9-rc3-bk4.orig/net/sched/estimator.c	2004-10-04 22:41:26.000000000 +0200
> +++ linux-2.6.9-rc3-bk4/net/sched/estimator.c	2004-10-04 22:53:54.000000000 +0200
> @@ -66,15 +66,11 @@
>  
>     * Minimal interval is HZ/4=250msec (it is the greatest common divisor
>       for HZ=100 and HZ=1024 8)), maximal interval
> -     is (HZ/4)*2^EST_MAX_INTERVAL = 8sec. Shorter intervals
> +     is (HZ*2^EST_MAX_INTERVAL)/4 = 8sec. Shorter intervals
>       are too expensive, longer ones can be implemented
>       at user level painlessly.
>   */
>  
> -#if (HZ%4) != 0
> -#error Bad HZ value.
> -#endif
> -
>  #define EST_MAX_INTERVAL	5
>  
>  struct qdisc_estimator
> @@ -128,7 +124,7 @@
>  		spin_unlock(e->stats_lock);
>  	}
>  
> -	mod_timer(&elist[idx].timer, jiffies + ((HZ/4)<<idx));
> +	mod_timer(&elist[idx].timer, jiffies + ((HZ<<idx)/4));
>  	read_unlock(&est_lock);
>  }
>  
> @@ -161,7 +157,7 @@
>  	if (est->next == NULL) {
>  		init_timer(&elist[est->interval].timer);
>  		elist[est->interval].timer.data = est->interval;
> -		elist[est->interval].timer.expires = jiffies + ((HZ/4)<<est->interval);
> +		elist[est->interval].timer.expires = jiffies + ((HZ<<est->interval)/4);
>  		elist[est->interval].timer.function = est_timer;
>  		add_timer(&elist[est->interval].timer);
>  	}
> 

Re: [PATCH] PKT_SCHED: Make rate estimator work for all platforms

[David S. Miller]

On 04 Oct 2004 19:47:34 -0400
jamal <hadi@cyberus.ca> wrote:

> Dave, Please apply all the patches (earlier 3 + this one) that Thomas
> posted.

Will do after I review it a bit more.

Thanks.

Re: [PATCH] PKT_SCHED: Make rate estimator work for all platforms

[David S. Miller]

On 04 Oct 2004 19:47:34 -0400
jamal <hadi@cyberus.ca> wrote:

> 
> Looking good.
> Dave, Please apply all the patches (earlier 3 + this one) that Thomas
> posted.

All applied, thanks guys.