From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Ingo Molnar <mingo@elte.hu>
Cc: 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 19:37:46 +1100 [thread overview]
Message-ID: <43AA65DA.6060003@yahoo.com.au> (raw)
In-Reply-To: <20051222082406.GA32052@elte.hu>
Ingo Molnar wrote:
> * Nick Piggin <nickpiggin@yahoo.com.au> wrote:
>
>
>>At the very least, the head waiter should not put itself on the end of
>>the FIFO when it finds the lock contended and waits again.
>
>
> It's on my list. I had this implemented a couple of days ago, but then
> profiled it and it turns out that the scenario isnt actually happening
> in any significant way, not even on the most extreme 512-task workloads.
> So i just removed the extra bloat. But i'll look at this again today,
> together with some 'max delay' statistics.
>
That would be good.
If it isn't happening in a significant quantity, then something else
must be responsible for the performance increase. Arjan guesses the
double wakeups which could be the case, but I'd still put my money
on this issue (or maybe it is a combination of both).
Either way it would be good to work out where the performance is
coming from, and I do think fixing this is a good idea for fairness
(even though it may not technically improve deterministic max
latencies because there are still race windows)
--
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 8:37 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
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 [this message]
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=43AA65DA.6060003@yahoo.com.au \
--to=nickpiggin@yahoo.com.au \
--cc=ak@suse.de \
--cc=akpm@osdl.org \
--cc=alan@lxorguk.ukuu.org.uk \
--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).