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From: Martin Devera <devik@cdi.cz>
To: David Miller <davem@davemloft.net>
Cc: linux-kernel@vger.kernel.org, kaber@trash.net, netdev@vger.kernel.org
Subject: Re: [PATCH 2.6.24 1/1] sch_htb: fix "too many events" situation
Date: Mon, 18 Feb 2008 11:08:09 +0100	[thread overview]
Message-ID: <47B95909.8060202@cdi.cz> (raw)
In-Reply-To: <20080218.001736.124204016.davem@davemloft.net>

David Miller wrote:
> From: Martin Devera <devik@cdi.cz>
> Date: Mon, 18 Feb 2008 09:03:52 +0100
> 
>> aha, ok, I'm not so informed about crossplatform issues.
>> I was also thining about looking at jiffies value and stop once
>> it is startjiffy+2, but with NO_HZ introduction, are jiffies
>> still incremented ?
> 
> There should always be at least once cpu tasked with incrementing
> jiffies.  Lots of stuff would break if not :-)
> 

Aha ok, so that when (at least one) cpu is busy then I can count on
jiffies incrementing via do_timer, can't I ?
So that I'd remove the loop limit altogether but limiting it to
1 or 2 jiffies to prevent livelock.
Like
max_jiff = jiffies+2; /* not +1 at we could be at +0.9999 now */
while (jiffies<max_jiff) do_hard_potentionaly_long_work();
if (more_work) schedule_to_next_jiffie();

This will keep event queue work load under 66% of system load which
seems reasonable to me.

Would you accept such solution ?

  reply	other threads:[~2008-02-18 10:08 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-14 23:02 [PATCH 2.6.24 1/1] sch_htb: fix "too many events" situation Martin Devera
2008-02-18  7:28 ` David Miller
2008-02-18  8:03   ` Martin Devera
2008-02-18  8:17     ` David Miller
2008-02-18 10:08       ` Martin Devera [this message]
2008-02-18 10:43         ` David Miller

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