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* VLAN GARP triggers a lot of timers if linux compiled with VLAN_8021Q_GVRP
@ 2010-09-29  0:35 didier
  2010-09-29  9:22 ` Patrick McHardy
  0 siblings, 1 reply; 3+ messages in thread
From: didier @ 2010-09-29  0:35 UTC (permalink / raw)
  To: netdev; +Cc: kaber

Hi,

In my understanding GARP is using a periodic timer but in net/802/garp.c:

garp_join_timer_arm()

delay = (u64)msecs_to_jiffies(garp_join_time)* net_random() >> 32;
mod_timer(&app->join_timer, jiffies +delay)

Isn't this stuff triggering a *lot* of events?

Didier

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: VLAN GARP triggers a lot of timers if linux compiled with VLAN_8021Q_GVRP
  2010-09-29  0:35 VLAN GARP triggers a lot of timers if linux compiled with VLAN_8021Q_GVRP didier
@ 2010-09-29  9:22 ` Patrick McHardy
  2010-09-29 11:02   ` didier
  0 siblings, 1 reply; 3+ messages in thread
From: Patrick McHardy @ 2010-09-29  9:22 UTC (permalink / raw)
  To: didier; +Cc: netdev

Am 29.09.2010 02:35, schrieb didier:
> Hi,
> 
> In my understanding GARP is using a periodic timer but in net/802/garp.c:
> 
> garp_join_timer_arm()
> 
> delay = (u64)msecs_to_jiffies(garp_join_time)* net_random() >> 32;
> mod_timer(&app->join_timer, jiffies +delay)
> 
> Isn't this stuff triggering a *lot* of events?

Yeah, something around 5-10 timers per second IIRC. There was an RFC
patch a while ago to only schedule the timer on-demand, I'll see
whether I can find it again.

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: VLAN GARP triggers a lot of timers if linux compiled with VLAN_8021Q_GVRP
  2010-09-29  9:22 ` Patrick McHardy
@ 2010-09-29 11:02   ` didier
  0 siblings, 0 replies; 3+ messages in thread
From: didier @ 2010-09-29 11:02 UTC (permalink / raw)
  To: Patrick McHardy; +Cc: netdev

Hi,
>
>> garp_join_timer_arm()
>>
>> delay = (u64)msecs_to_jiffies(garp_join_time)* net_random() >> 32;
>> mod_timer(&app->join_timer, jiffies +delay)
>>
>> Isn't this stuff triggering a *lot* of events?
>
> Yeah, something around 5-10 timers per second IIRC. There was an RFC
> patch a while ago to only schedule the timer on-demand, I'll see
> whether I can find it again.

But with this formula delay can be often rather small, or do I miss something?

Here on an idle box with two vlans vmstat output shows  burst of up to
15000 context switches per seconds.

Didier

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2010-09-29 11:02 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2010-09-29  0:35 VLAN GARP triggers a lot of timers if linux compiled with VLAN_8021Q_GVRP didier
2010-09-29  9:22 ` Patrick McHardy
2010-09-29 11:02   ` didier

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