From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Arjan van de Ven <arjan@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>,
Jes Sorensen <jes@trained-monkey.org>,
Linus Torvalds <torvalds@osdl.org>,
lkml <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>,
Arjan van de Ven <arjanv@infradead.org>,
Zwane Mwaikambo <zwane@arm.linux.org.uk>,
Oleg Nesterov <oleg@tv-sign.ru>,
David Howells <dhowells@redhat.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Benjamin LaHaise <bcrl@kvack.org>,
Steven Rostedt <rostedt@goodmis.org>,
Christoph Hellwig <hch@infradead.org>, Andi Kleen <ak@suse.de>,
Russell King <rmk+lkml@arm.linux.org.uk>,
Nicolas Pitre <nico@cam.org>
Subject: Re: [patch 0/8] mutex subsystem, ANNOUNCE
Date: Thu, 22 Dec 2005 19:10:35 +1100 [thread overview]
Message-ID: <43AA5F7B.7010407@yahoo.com.au> (raw)
In-Reply-To: <1135238423.2940.1.camel@laptopd505.fenrus.org>
Arjan van de Ven wrote:
> On Thu, 2005-12-22 at 18:56 +1100, Nick Piggin wrote:
>
>>Ingo Molnar wrote:
>>
>>>* Nick Piggin <nickpiggin@yahoo.com.au> wrote:
>>>
>>>
>>>
>>>>It would be nice to first do a run with a fair implementation of
>>>>mutexes.
>>>
>>>
>>>which fairness implementation do you mean - the one where all tasks will
>>>get the lock in fair FIFO order, and a 'lucky bastard' cannot steal the
>>>lock from waiters and thus put them at an indefinite disadvantage?
>>>
>>
>>I guess so. I'm not so worried about the rare 'lucky bastard' ie. a
>>lock request coming in concurrently, but rather the naturally favoured
>>'this CPU' taking the lock again after waking up the head waiter but
>>before it gets a chance to run / transfer the cacheline.
>
>
> that's just the most evil lucky bastard....
>
I'd probably just call "bastard": it is probably _unlucky_ when _doesn't_
get to retake the lock, judging by the factor-of-4 speedup that Jes
demonstrated.
Which might be the right thing to do, but having the front waiter go to
the back of the queue I think is not.
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
next prev parent reply other threads:[~2005-12-22 8:10 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-21 15:54 [patch 0/8] mutex subsystem, ANNOUNCE Ingo Molnar
2005-12-21 16:04 ` Arjan van de Ven
2005-12-21 18:07 ` Jes Sorensen
2005-12-22 2:36 ` Nick Piggin
2005-12-22 2:57 ` Nick Piggin
2005-12-22 7:19 ` Ingo Molnar
2005-12-22 7:56 ` Nick Piggin
2005-12-22 8:00 ` Arjan van de Ven
2005-12-22 8:10 ` Nick Piggin [this message]
2005-12-22 8:21 ` Arjan van de Ven
2005-12-22 8:32 ` Nick Piggin
2005-12-22 8:24 ` Ingo Molnar
2005-12-22 8:37 ` Nick Piggin
2005-12-21 22:43 ` Nicolas Pitre
2005-12-21 22:43 ` [patch 1/3] mutex subsystem: fix additions to the ARM atomic.h Nicolas Pitre
2005-12-21 22:44 ` [patch 2/3] mutex subsystem: add new atomic primitives Nicolas Pitre
2005-12-21 22:44 ` [patch 3/3] mutex subsystem: move the core to the new atomic helpers Nicolas Pitre
2005-12-21 23:12 ` Ingo Molnar
2005-12-22 1:16 ` Matt Mackall
2005-12-22 6:50 ` Nicolas Pitre
2005-12-22 6:51 ` [patch 2/5] mutex subsystem: add architecture specific mutex primitives Nicolas Pitre
2005-12-22 7:44 ` Nick Piggin
2005-12-22 8:03 ` Nick Piggin
2005-12-22 6:52 ` [patch 1/5] mutex subsystem: fix asm-arm/atomic.h Nicolas Pitre
2005-12-22 6:53 ` [patch 3/5] mutex subsystem: move the core to the new atomic helpers Nicolas Pitre
2005-12-22 6:53 ` [patch 4/5] mutex subsystem: allow architecture defined fast path for mutex_lock_interruptible Nicolas Pitre
2005-12-22 6:53 ` [patch 5/5] mutex subsystem: allow for the fast path to be inlined Nicolas Pitre
2005-12-21 22:36 [patch 0/8] mutex subsystem, ANNOUNCE Ingo Molnar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=43AA5F7B.7010407@yahoo.com.au \
--to=nickpiggin@yahoo.com.au \
--cc=ak@suse.de \
--cc=akpm@osdl.org \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=arjan@infradead.org \
--cc=arjanv@infradead.org \
--cc=bcrl@kvack.org \
--cc=dhowells@redhat.com \
--cc=hch@infradead.org \
--cc=jes@trained-monkey.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=nico@cam.org \
--cc=oleg@tv-sign.ru \
--cc=rmk+lkml@arm.linux.org.uk \
--cc=rostedt@goodmis.org \
--cc=torvalds@osdl.org \
--cc=zwane@arm.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).