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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Buytaert_Steven@emc.com
Cc: andi@firstfloor.org, linux-kernel@vger.kernel.org
Subject: Re: sched_yield proposals/rationale
Date: Thu, 12 Apr 2007 23:27:22 +1000	[thread overview]
Message-ID: <461E33BA.2030104@yahoo.com.au> (raw)
In-Reply-To: <585DC2133F7C974F87D4EC432896F1720309F3DB@CORPUSMX10A.corp.emc.com>

Buytaert_Steven@emc.com wrote:
>>-----Original Message-----
>>From: Andi Kleen
>>[ ... about use of sched_yield ...]
>>On the other hand when they fix their code to not rely on sched_yield
>>but use [...]
> 
> 
> Agreed, but $ find . -name "*.[ch]" | xargs grep -E "yield[ ]*\(" | wc over
> the 2.6.16 kernel yields 105 hits, note including comments...

Most of these (in core code, anyway) seem to use yield when they really don't
care about running for a while.

> An interesting spot is e.g. fs/buffer.c free_more_memory()

This one should be pretty rare (actually I think it is dead code in practice,
due to the way the page allocator works).

Avoiding sched_yield is a really good idea outside realtime scheduling. Since
we have gone this far with the current semantics, I think it would be sad to
back down now.

It would be nice if you could pressure those other components to adapt :)

-- 
SUSE Labs, Novell Inc.

  reply	other threads:[~2007-04-12 13:27 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-04-12  8:31 sched_yield proposals/rationale Buytaert_Steven
2007-04-12  9:48 ` Sven-Thorsten Dietrich
2007-04-12 13:31 ` Andi Kleen
2007-04-12 13:05   ` Buytaert_Steven
2007-04-12 13:27     ` Nick Piggin [this message]
2007-04-12 22:00       ` William Lee Irwin III
2007-04-12 13:31     ` Andi Kleen
2007-04-12 14:15       ` Buytaert_Steven
2007-04-12 21:04         ` Thomas Gleixner
2007-04-12 22:32         ` Bill Davidsen
2007-04-13  5:36           ` Buytaert_Steven
2007-04-13 19:46             ` Mark Lord
2007-04-17 19:37               ` Bill Davidsen
2007-04-18  5:40                 ` Buytaert_Steven
2007-04-12 21:37   ` William Lee Irwin III

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