From: john cooper <john.cooper@timesys.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Daniel Walker <dwalker@mvista.com>,
linux-kernel@vger.kernel.org,
john cooper <john.cooper@timesys.com>
Subject: Re: RT and Cascade interrupts
Date: Fri, 13 May 2005 09:12:22 -0400 [thread overview]
Message-ID: <4284A7B6.4090408@timesys.com> (raw)
In-Reply-To: <20050513074439.GB25458@elte.hu>
Ingo Molnar wrote:
> * Daniel Walker <dwalker@mvista.com> wrote:
>
>
>> It seems like the cascade interrupts could run in threads, but
>>i386 doesn't, and I know ARM crashed with cascades in threads. You may
>>have a bit of a slow down, but it seems possible. Does anyone have
>>some reasoning for why we aren't running the cascades in threads?
>
>
> are the x86 cascade interrupts real ones in fact? Normally they should
> never trigger directly. (except on ARM which has a completely different
> notion of cascade irq)
I just caught this thread in the corner of my eye.
I'm seeing the BUG assert in kernel/timers.c:cascade()
kick in (tmp->base is somehow 0) during a test which
creates a few tasks of priority higher than ksoftirqd.
This race doesn't happen if ksoftirqd's priority is
elevated (eg: chrt -f -p 75 2) so the -RT patch might
be opening up a window here.
I'm in the process of investigating this and see a few
potential suspects but was wondering if anyone else has
seen this behavior?
-john
--
john.cooper@timesys.com
next prev parent reply other threads:[~2005-05-13 13:13 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-12 14:43 RT and Cascade interrupts Daniel Walker
2005-05-13 7:44 ` Ingo Molnar
2005-05-13 13:12 ` john cooper [this message]
2005-05-24 16:32 ` john cooper
2005-05-27 7:25 ` Ingo Molnar
2005-05-27 13:53 ` john cooper
-- strict thread matches above, loose matches on Subject: below --
2005-05-27 16:47 Oleg Nesterov
2005-05-27 23:37 ` john cooper
2005-05-28 8:52 ` Oleg Nesterov
2005-05-28 14:02 ` john cooper
2005-05-28 16:34 ` Oleg Nesterov
2005-05-28 17:48 ` john cooper
2005-05-28 20:35 ` Trond Myklebust
2005-05-29 3:12 ` john cooper
2005-05-29 7:40 ` Trond Myklebust
2005-05-30 21:32 ` john cooper
2005-05-31 23:09 ` john cooper
2005-06-01 14:22 ` Oleg Nesterov
2005-06-01 18:05 ` john cooper
2005-06-01 18:31 ` Trond Myklebust
2005-06-01 19:20 ` john cooper
2005-06-01 19:46 ` Trond Myklebust
2005-06-01 20:21 ` Trond Myklebust
2005-06-01 20:59 ` john cooper
2005-06-01 22:51 ` Trond Myklebust
2005-06-01 23:09 ` Trond Myklebust
2005-06-02 3:31 ` john cooper
2005-06-02 4:26 ` Trond Myklebust
2005-06-09 23:17 ` George Anzinger
2005-06-09 23:52 ` john cooper
2005-05-29 11:31 ` Oleg Nesterov
2005-05-29 13:58 ` Trond Myklebust
2005-05-30 14:50 ` Ingo Molnar
2005-05-28 22:17 ` Trond Myklebust
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