From: Arnd Bergmann <arnd@arndb.de>
To: linuxppc-dev@lists.ozlabs.org
Cc: linuxppc-dev <linuxppc-dev@ozlabs.org>,
Sean MacLennan <smaclennan@pikatech.com>
Subject: Re: Floating point in the kernel
Date: Thu, 10 Dec 2009 22:35:47 +0100 [thread overview]
Message-ID: <200912102235.47985.arnd@arndb.de> (raw)
In-Reply-To: <20091210153359.3a480488@lappy.seanm.ca>
On Thursday 10 December 2009, Sean MacLennan wrote:
> To be honest, I can't find why we are scheduling :( They only way we
> give up the CPU is with locking... and none of the locks where hit
> during the problem. We also never get near our timeslice... the longest
> run I saw when the problem happened was 670us.
>
> Is there a way to disable scheduling? We currently do not have preempt
> enabled... but may in the future.
If you do preempt_disable(), it should give you a nice oops with a backtrace
at the point where an actual schedule happens.
The sequence should be something like
preempt_disable();
enable_kernel_fp();
/* use FP here */
preempt_enable();
/* may schedule again */
Arnd <><
next prev parent reply other threads:[~2009-12-10 21:35 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-10 18:13 Floating point in the kernel Sean MacLennan
2009-12-10 20:19 ` Benjamin Herrenschmidt
2009-12-10 20:33 ` Sean MacLennan
2009-12-10 20:56 ` Benjamin Herrenschmidt
2009-12-10 21:35 ` Arnd Bergmann [this message]
2009-12-11 0:17 ` Sean MacLennan
2009-12-11 11:28 ` Arnd Bergmann
2009-12-10 20:32 ` arnd
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