From: Ingo Molnar <mingo@elte.hu>
To: Daniel Walker <dwalker@mvista.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Interrupt starvation points
Date: Fri, 11 Feb 2005 18:30:25 +0100 [thread overview]
Message-ID: <20050211173025.GA17387@elte.hu> (raw)
In-Reply-To: <1108141521.21940.44.camel@dhcp153.mvista.com>
* Daniel Walker <dwalker@mvista.com> wrote:
> I found some points during schedule when interrupts are off
> for long periods . These two patches seem to help. One enables
> interrupts inside schedule() , so that interrupts are enabled after
> each need-resched loop, then disabled again before __schedule() is
> called.
>
> The other patch enabled interrupt before calling up on
> kernel_sem ..This one could use some thinking over. I did this cause
> up() is very expensive on ARM , and combined with the looping above
> interrupts can stay off for a long time ..
i'm wondering what the best approach would be. Right now if
DIRECT_PREEMPT is enabled [it's disabled currently] and a higher-prio
task has been woken up we switch to it without ever enabling interrupts
again. Re-enabling interrupts during schedule() will reduce irq
latencies but will lengthen critical sections.
Ingo
next prev parent reply other threads:[~2005-02-11 17:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-11 17:05 Daniel Walker
2005-02-11 17:30 ` Ingo Molnar [this message]
2005-02-11 17:36 ` Daniel Walker
2005-02-11 20:04 ` Russell King
2005-02-11 21:52 ` Daniel Walker
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