From: "Kevin D. Kissell" <kevink@mips.com>
To: "Jason Gunthorpe" <jgg@debian.org>
Cc: <linux-mips@oss.sgi.com>
Subject: Re: patches for test-and-set without ll/sc (Re: thread-ready ABIs)
Date: Tue, 22 Jan 2002 19:19:55 +0100 [thread overview]
Message-ID: <00e801c1a371$65c92ec0$0deca8c0@Ulysses> (raw)
In-Reply-To: Pine.LNX.3.96.1020122110419.20690A-100000@wakko.deltatee.com
> On Tue, 22 Jan 2002, Kevin D. Kissell wrote:
>
> > The idea leverages off the fact that a branch likely
> > instruction performs a kind of conditional execution.
> > The instruction in the delay slot is executed only if
> > the branch is taken. This can be used to synthesize
> > a conditional store. The user level code for a simple
> > atomic increment, for example, would look something
> > like this:
>
> Hmm, could you use this to take the race out of the kernel wait loop
> too? Ie use current->need_resched as the test and 'wait' as the
> conditional operation.
It's quite possible. But remember that it won't work on
an R3000. R39xx yes, but not an R3K "classic".
Kevin K.
WARNING: multiple messages have this Message-ID (diff)
From: "Kevin D. Kissell" <kevink@mips.com>
To: Jason Gunthorpe <jgg@debian.org>
Cc: linux-mips@oss.sgi.com
Subject: Re: patches for test-and-set without ll/sc (Re: thread-ready ABIs)
Date: Tue, 22 Jan 2002 19:19:55 +0100 [thread overview]
Message-ID: <00e801c1a371$65c92ec0$0deca8c0@Ulysses> (raw)
Message-ID: <20020122181955.OTDtGj_9Hl9LhVI0T-sMyqGO3Eeoepua7apG-HfAn0M@z> (raw)
In-Reply-To: Pine.LNX.3.96.1020122110419.20690A-100000@wakko.deltatee.com
> On Tue, 22 Jan 2002, Kevin D. Kissell wrote:
>
> > The idea leverages off the fact that a branch likely
> > instruction performs a kind of conditional execution.
> > The instruction in the delay slot is executed only if
> > the branch is taken. This can be used to synthesize
> > a conditional store. The user level code for a simple
> > atomic increment, for example, would look something
> > like this:
>
> Hmm, could you use this to take the race out of the kernel wait loop
> too? Ie use current->need_resched as the test and 'wait' as the
> conditional operation.
It's quite possible. But remember that it won't work on
an R3000. R39xx yes, but not an R3K "classic".
Kevin K.
next prev parent reply other threads:[~2002-01-22 19:19 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-22 14:25 patches for test-and-set without ll/sc (Re: thread-ready ABIs) Machida Hiroyuki
2002-01-22 17:16 ` Kevin D. Kissell
2002-01-22 17:16 ` Kevin D. Kissell
2002-01-22 18:08 ` Jason Gunthorpe
2002-01-22 18:19 ` Kevin D. Kissell [this message]
2002-01-22 18:19 ` Kevin D. Kissell
2002-01-23 5:56 ` Machida Hiroyuki
2002-01-23 8:38 ` Kevin D. Kissell
2002-01-23 8:38 ` Kevin D. Kissell
2002-01-24 18:59 ` Ralf Baechle
2002-01-25 4:39 ` Machida Hiroyuki
2002-01-25 7:25 ` Kevin D. Kissell
2002-01-25 7:25 ` Kevin D. Kissell
-- strict thread matches above, loose matches on Subject: below --
2002-01-20 10:38 thread-ready ABIs Machida Hiroyuki
2002-01-20 11:58 ` Kevin D. Kissell
2002-01-20 13:16 ` Machida Hiroyuki
2002-01-22 6:27 ` patches for test-and-set without ll/sc (Re: thread-ready ABIs) Machida Hiroyuki
2002-01-22 6:37 ` Ulrich Drepper
2002-01-22 6:46 ` Machida Hiroyuki
2002-01-22 6:56 ` Ulrich Drepper
2002-01-24 9:56 ` Andreas Jaeger
2002-01-24 9:56 ` Andreas Jaeger
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