[patch 01/11] user of the jiffies rounding code: Networking

[patch 01/11] user of the jiffies rounding code: Networking

[akpm]

From: Arjan van de Ven <arjan@linux.intel.com>

This patch introduces users of the round_jiffies() function in the networking
code.

These timers all were of the "about once a second" or "about once every X
seconds" variety and several showed up in the "what wakes the cpu up" profiles
that the tickless patches provide.  Some timers are highly dynamic based on
network load; but even on low activity systems they still show up so the
rounding is done only in cases of low activity, allowing higher frequency
timers in the high activity case.

The various hardware watchdogs are an obvious case; they run every 2 seconds
but aren't otherwise specific of exactly when they need to run.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/net/e1000/e1000_main.c |    6 +++---
 net/core/dst.c                 |    9 ++++++++-
 net/core/neighbour.c           |    5 ++++-
 net/sched/sch_generic.c        |    2 +-
 4 files changed, 16 insertions(+), 6 deletions(-)

diff -puN drivers/net/e1000/e1000_main.c~user-of-the-jiffies-rounding-code-networking drivers/net/e1000/e1000_main.c
--- a/drivers/net/e1000/e1000_main.c~user-of-the-jiffies-rounding-code-networking
+++ a/drivers/net/e1000/e1000_main.c
@@ -2652,7 +2652,7 @@ e1000_watchdog(unsigned long data)
 
 			netif_carrier_on(netdev);
 			netif_wake_queue(netdev);
-			mod_timer(&adapter->phy_info_timer, jiffies + 2 * HZ);
+			mod_timer(&adapter->phy_info_timer, round_jiffies(jiffies + 2 * HZ));
 			adapter->smartspeed = 0;
 		} else {
 			/* make sure the receive unit is started */
@@ -2669,7 +2669,7 @@ e1000_watchdog(unsigned long data)
 			DPRINTK(LINK, INFO, "NIC Link is Down\n");
 			netif_carrier_off(netdev);
 			netif_stop_queue(netdev);
-			mod_timer(&adapter->phy_info_timer, jiffies + 2 * HZ);
+			mod_timer(&adapter->phy_info_timer, round_jiffies(jiffies + 2 * HZ));
 
 			/* 80003ES2LAN workaround--
 			 * For packet buffer work-around on link down event;
@@ -2721,7 +2721,7 @@ e1000_watchdog(unsigned long data)
 		e1000_rar_set(&adapter->hw, adapter->hw.mac_addr, 0);
 
 	/* Reset the timer */
-	mod_timer(&adapter->watchdog_timer, jiffies + 2 * HZ);
+	mod_timer(&adapter->watchdog_timer, round_jiffies(jiffies + 2 * HZ));
 }
 
 enum latency_range {
diff -puN net/core/dst.c~user-of-the-jiffies-rounding-code-networking net/core/dst.c
--- a/net/core/dst.c~user-of-the-jiffies-rounding-code-networking
+++ a/net/core/dst.c
@@ -99,7 +99,14 @@ static void dst_run_gc(unsigned long dum
 	printk("dst_total: %d/%d %ld\n",
 	       atomic_read(&dst_total), delayed,  dst_gc_timer_expires);
 #endif
-	mod_timer(&dst_gc_timer, jiffies + dst_gc_timer_expires);
+	/* if the next desired timer is more than 4 seconds in the future
+	 * then round the timer to whole seconds
+	 */
+	if (dst_gc_timer_expires > 4*HZ)
+		mod_timer(&dst_gc_timer,
+			round_jiffies(jiffies + dst_gc_timer_expires));
+	else
+		mod_timer(&dst_gc_timer, jiffies + dst_gc_timer_expires);
 
 out:
 	spin_unlock(&dst_lock);
diff -puN net/core/neighbour.c~user-of-the-jiffies-rounding-code-networking net/core/neighbour.c
--- a/net/core/neighbour.c~user-of-the-jiffies-rounding-code-networking
+++ a/net/core/neighbour.c
@@ -696,7 +696,10 @@ next_elt:
 	if (!expire)
 		expire = 1;
 
- 	mod_timer(&tbl->gc_timer, now + expire);
+	if (expire>HZ)
+		mod_timer(&tbl->gc_timer, round_jiffies(now + expire));
+	else
+	 	mod_timer(&tbl->gc_timer, now + expire);
 
 	write_unlock(&tbl->lock);
 }
diff -puN net/sched/sch_generic.c~user-of-the-jiffies-rounding-code-networking net/sched/sch_generic.c
--- a/net/sched/sch_generic.c~user-of-the-jiffies-rounding-code-networking
+++ a/net/sched/sch_generic.c
@@ -209,7 +209,7 @@ static void dev_watchdog(unsigned long a
 				       dev->name);
 				dev->tx_timeout(dev);
 			}
-			if (!mod_timer(&dev->watchdog_timer, jiffies + dev->watchdog_timeo))
+			if (!mod_timer(&dev->watchdog_timer, round_jiffies(jiffies + dev->watchdog_timeo)))
 				dev_hold(dev);
 		}
 	}
_

Re: [patch 01/11] user of the jiffies rounding code: Networking

[David Miller]

From: akpm@linux-foundation.org
Date: Mon, 05 Feb 2007 16:30:52 -0800

> From: Arjan van de Ven <arjan@linux.intel.com>
> 
> This patch introduces users of the round_jiffies() function in the networking
> code.
> 
> These timers all were of the "about once a second" or "about once every X
> seconds" variety and several showed up in the "what wakes the cpu up" profiles
> that the tickless patches provide.  Some timers are highly dynamic based on
> network load; but even on low activity systems they still show up so the
> rounding is done only in cases of low activity, allowing higher frequency
> timers in the high activity case.
> 
> The various hardware watchdogs are an obvious case; they run every 2 seconds
> but aren't otherwise specific of exactly when they need to run.
> 
> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

I pulled in everything except the e1000 driver change, Jeff please
suck that in, thanks.

Arjan, btw:

> +	if (dst_gc_timer_expires > 4*HZ)
> +		mod_timer(&dst_gc_timer,
> +			round_jiffies(jiffies + dst_gc_timer_expires));
> +	else
> +		mod_timer(&dst_gc_timer, jiffies + dst_gc_timer_expires);
   ^^^^^^^^^^^^^

That line begins "TAB SPACE TAB", and lo' and behold GIT
catch this when I applied it :-)  I fixed it up by hand
and reapplied, so don't worry about this instance.

Re: [patch 01/11] user of the jiffies rounding code: Networking

[Auke Kok]

David Miller wrote:
> From: akpm@linux-foundation.org
> Date: Mon, 05 Feb 2007 16:30:52 -0800
> 
>> From: Arjan van de Ven <arjan@linux.intel.com>
>>
>> This patch introduces users of the round_jiffies() function in the networking
>> code.
>>
>> These timers all were of the "about once a second" or "about once every X
>> seconds" variety and several showed up in the "what wakes the cpu up" profiles
>> that the tickless patches provide.  Some timers are highly dynamic based on
>> network load; but even on low activity systems they still show up so the
>> rounding is done only in cases of low activity, allowing higher frequency
>> timers in the high activity case.
>>
>> The various hardware watchdogs are an obvious case; they run every 2 seconds
>> but aren't otherwise specific of exactly when they need to run.
>>
>> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
>> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> 
> I pulled in everything except the e1000 driver change, Jeff please
> suck that in, thanks.

Jeff,

And add my:

Acked-by: Auke Kok <auke-jan.h.kok@intel.com>


Thanks

Auke

> 
> Arjan, btw:
> 
>> +	if (dst_gc_timer_expires > 4*HZ)
>> +		mod_timer(&dst_gc_timer,
>> +			round_jiffies(jiffies + dst_gc_timer_expires));
>> +	else
>> +		mod_timer(&dst_gc_timer, jiffies + dst_gc_timer_expires);
>    ^^^^^^^^^^^^^
> 
> That line begins "TAB SPACE TAB", and lo' and behold GIT
> catch this when I applied it :-)  I fixed it up by hand
> and reapplied, so don't worry about this instance.
> 
> -
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