From: Linus Torvalds <torvalds@linux-foundation.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Mike Galbraith <efault@gmx.de>
Subject: Re: [git pull] scheduler updates
Date: Sat, 8 Nov 2008 10:38:43 -0800 (PST) [thread overview]
Message-ID: <alpine.LFD.2.00.0811081035370.3468@nehalem.linux-foundation.org> (raw)
In-Reply-To: <alpine.LFD.2.00.0811081026280.3468@nehalem.linux-foundation.org>
On Sat, 8 Nov 2008, Linus Torvalds wrote:
>
> Can we please just remove that idiocy? Or can somebody give a _sane_
> argument for it?
Btw, the only _possible_ sane argument I see is
- two consecutive rdtsc calls
- timing the code in between
- the code in between is not self-serializing
and quite frankly, if that's the case, then it's _that_ code that should
have the barriers, not some generic "[v]get_cycles()".
IOW, the rdtsc_barrier may make sense when you're synchronizing the TSC to
some other hardware event (eg the "tie the TSC to the HPET" kind of
code), but then the barriers are about the code, not about the TSC access
itself.
Linus
next prev parent reply other threads:[~2008-11-08 18:39 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-08 17:02 Ingo Molnar
2008-11-08 18:28 ` Linus Torvalds
2008-11-08 18:38 ` Linus Torvalds [this message]
2008-11-08 18:41 ` Arjan van de Ven
2008-11-08 19:00 ` Linus Torvalds
2008-11-08 19:05 ` Ingo Molnar
2008-11-08 19:20 ` Linus Torvalds
2008-11-08 19:29 ` Ingo Molnar
2008-11-17 22:43 ` Venki Pallipadi
2008-11-17 22:50 ` Ingo Molnar
2008-11-17 23:04 ` Venki Pallipadi
2008-11-17 23:13 ` Ingo Molnar
2008-11-08 19:40 ` Ingo Molnar
2008-11-08 19:10 ` Ingo Molnar
2008-11-08 18:52 ` Ingo Molnar
2008-11-08 18:57 ` Ingo Molnar
2008-11-08 19:32 ` Ingo Molnar
-- strict thread matches above, loose matches on Subject: below --
2018-02-06 21:38 [GIT PULL] " Ingo Molnar
2008-03-21 16:23 [git pull] " Ingo Molnar
2008-02-29 18:04 Ingo Molnar
2008-02-13 15:58 Ingo Molnar
2008-01-31 21:54 Ingo Molnar
2007-12-30 16:45 Ingo Molnar
2007-10-24 16:39 Ingo Molnar
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