From: Ingo Molnar <mingo@elte.hu>
To: Christoph Hellwig <hch@infradead.org>,
Zach Brown <zach.brown@oracle.com>,
linux-kernel@vger.kernel.org, linux-aio@kvack.org,
Suparna Bhattacharya <suparna@in.ibm.com>,
Benjamin LaHaise <bcrl@kvack.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 2 of 4] Introduce i386 fibril scheduling
Date: Thu, 1 Feb 2007 14:52:15 +0100 [thread overview]
Message-ID: <20070201135215.GA23477@elte.hu> (raw)
In-Reply-To: <20070201131903.GA24683@infradead.org>
* Christoph Hellwig <hch@infradead.org> wrote:
> I tend to agree. Note that there is one thing we should be doing one
> one day (not only if we want to use it for aio) is to make kernel
> threads more lightweight. There a lot of baggae we keep around in
> task_struct and co that only makes sense for threads that have a user
> space part and aren't or shouldn't be needed for a purely
> kernel-resistant thread.
yeah. I'm totally open to such efforts. I'd also be most happy if this
was primarily driven via the KAIO effort: i.e. to implement it via
kernel threads and then to benchmark the hell out of it. I volunteer to
fix whatever fat kernel thread handling has left.
and if people agree with me that 'native' state-machine driven KAIO is
where we want to ultimately achieve (it is certainly the best performing
implementation) then i dont see the point in fibrils as an interim
mechanism anyway. Lets just hide AIO complexities from userspace via
kernel threads, and optimize this via two methods: by making kernel
threads faster, and by simultaneously and gradually converting as much
KAIO code to a native state machine - which would not need any kind of
kernel thread help anyway.
(plus as i mentioned previously, co-scheduling kernel threads with
related user space threads on the same CPU might be something useful too
- not just for KAIO, and we could add that too.)
also, we context-switch kernel threads in 350 nsecs on current hardware
and the -rt kernel is certainly happy with that and runs all hardirqs
and softirqs in separate kernel thread contexts. There's not /that/ much
fat left to cut off - and if there's something more to optimize there
then there are a good number of projects interested in that, not just
the KAIO effort :)
Ingo
next prev parent reply other threads:[~2007-02-01 13:54 UTC|newest]
Thread overview: 153+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-30 20:39 [PATCH 0 of 4] Generic AIO by scheduling stacks Zach Brown
2007-01-30 20:39 ` [PATCH 1 of 4] Introduce per_call_chain() Zach Brown
2007-01-30 20:39 ` [PATCH 2 of 4] Introduce i386 fibril scheduling Zach Brown
2007-02-01 8:36 ` Ingo Molnar
2007-02-01 13:02 ` Ingo Molnar
2007-02-01 13:19 ` Christoph Hellwig
2007-02-01 13:52 ` Ingo Molnar [this message]
2007-02-01 17:13 ` Mark Lord
2007-02-01 18:02 ` Ingo Molnar
2007-02-02 13:23 ` Andi Kleen
2007-02-01 21:52 ` Zach Brown
2007-02-01 22:23 ` Benjamin LaHaise
2007-02-01 22:37 ` Zach Brown
2007-02-02 13:22 ` Andi Kleen
2007-02-01 20:07 ` Linus Torvalds
2007-02-02 10:49 ` Ingo Molnar
2007-02-02 15:56 ` Linus Torvalds
2007-02-02 19:59 ` Alan
2007-02-02 20:14 ` Linus Torvalds
2007-02-02 20:58 ` Davide Libenzi
2007-02-02 21:09 ` Linus Torvalds
2007-02-02 21:30 ` Alan
2007-02-02 21:30 ` Linus Torvalds
2007-02-02 22:42 ` Ingo Molnar
2007-02-02 23:01 ` Linus Torvalds
2007-02-02 23:17 ` Linus Torvalds
2007-02-03 0:04 ` Alan
2007-02-03 0:23 ` bert hubert
2007-02-02 22:48 ` Alan
2007-02-05 16:44 ` Zach Brown
2007-02-02 22:21 ` Ingo Molnar
2007-02-02 22:49 ` Linus Torvalds
2007-02-02 23:55 ` Ingo Molnar
2007-02-03 0:56 ` Linus Torvalds
2007-02-03 7:15 ` Suparna Bhattacharya
2007-02-03 8:23 ` Ingo Molnar
2007-02-03 9:25 ` Matt Mackall
2007-02-03 10:03 ` Ingo Molnar
2007-02-05 17:44 ` Zach Brown
2007-02-05 19:26 ` Davide Libenzi
2007-02-05 19:41 ` Zach Brown
2007-02-05 20:10 ` Davide Libenzi
2007-02-05 20:21 ` Zach Brown
2007-02-05 20:42 ` Linus Torvalds
2007-02-05 20:39 ` Linus Torvalds
2007-02-05 21:09 ` Davide Libenzi
2007-02-05 21:31 ` Kent Overstreet
2007-02-06 20:25 ` Davide Libenzi
2007-02-06 20:46 ` Linus Torvalds
2007-02-06 21:16 ` David Miller
2007-02-06 21:28 ` Linus Torvalds
2007-02-06 21:31 ` David Miller
2007-02-06 21:46 ` Eric Dumazet
2007-02-06 21:50 ` Linus Torvalds
2007-02-06 22:28 ` Zach Brown
2007-02-06 22:45 ` Kent Overstreet
2007-02-06 23:04 ` Linus Torvalds
2007-02-07 1:22 ` Kent Overstreet
2007-02-06 23:23 ` Davide Libenzi
2007-02-06 23:39 ` Joel Becker
2007-02-06 23:56 ` Davide Libenzi
2007-02-07 0:06 ` Joel Becker
2007-02-07 0:23 ` Davide Libenzi
2007-02-07 0:44 ` Joel Becker
2007-02-07 1:15 ` Davide Libenzi
2007-02-07 1:24 ` Kent Overstreet
2007-02-07 1:30 ` Joel Becker
2007-02-07 6:16 ` Michael K. Edwards
2007-02-07 9:17 ` Michael K. Edwards
2007-02-07 9:37 ` Michael K. Edwards
2007-02-06 0:32 ` Davide Libenzi
2007-02-05 21:21 ` Zach Brown
2007-02-02 23:37 ` Davide Libenzi
2007-02-03 0:02 ` Davide Libenzi
2007-02-05 17:12 ` Zach Brown
2007-02-05 18:24 ` Davide Libenzi
2007-02-05 21:44 ` David Miller
2007-02-06 0:15 ` Davide Libenzi
2007-02-05 21:36 ` bert hubert
2007-02-05 21:57 ` Linus Torvalds
2007-02-05 22:07 ` bert hubert
2007-02-05 22:15 ` Zach Brown
2007-02-05 22:34 ` Davide Libenzi
2007-02-06 0:27 ` Scot McKinley
2007-02-06 0:48 ` David Miller
2007-02-06 0:48 ` Joel Becker
2007-02-05 17:02 ` Zach Brown
2007-02-05 18:52 ` Davide Libenzi
2007-02-05 19:20 ` Zach Brown
2007-02-05 19:38 ` Davide Libenzi
2007-02-04 5:12 ` Davide Libenzi
2007-02-05 17:54 ` Zach Brown
2007-01-30 20:39 ` [PATCH 3 of 4] Teach paths to wake a specific void * target instead of a whole task_struct Zach Brown
2007-01-30 20:39 ` [PATCH 4 of 4] Introduce aio system call submission and completion system calls Zach Brown
2007-01-31 8:58 ` Andi Kleen
2007-01-31 17:15 ` Zach Brown
2007-01-31 17:21 ` Andi Kleen
2007-01-31 19:23 ` Zach Brown
2007-02-01 11:13 ` Suparna Bhattacharya
2007-02-01 19:50 ` Trond Myklebust
2007-02-02 7:19 ` Suparna Bhattacharya
2007-02-02 7:45 ` Andi Kleen
2007-02-01 22:18 ` Zach Brown
2007-02-02 3:35 ` Suparna Bhattacharya
2007-02-01 20:26 ` bert hubert
2007-02-01 21:29 ` Zach Brown
2007-02-02 7:12 ` bert hubert
2007-02-04 5:12 ` Davide Libenzi
2007-01-30 21:58 ` [PATCH 0 of 4] Generic AIO by scheduling stacks Linus Torvalds
2007-01-30 22:23 ` Linus Torvalds
2007-01-30 22:53 ` Zach Brown
2007-01-30 22:40 ` Zach Brown
2007-01-30 22:53 ` Linus Torvalds
2007-01-30 23:45 ` Zach Brown
2007-01-31 2:07 ` Benjamin Herrenschmidt
2007-01-31 2:04 ` Benjamin Herrenschmidt
2007-01-31 2:46 ` Linus Torvalds
2007-01-31 3:02 ` Linus Torvalds
2007-01-31 10:50 ` Xavier Bestel
2007-01-31 19:28 ` Zach Brown
2007-01-31 17:59 ` Zach Brown
2007-01-31 5:16 ` Benjamin Herrenschmidt
2007-01-31 5:36 ` Nick Piggin
2007-01-31 5:51 ` Nick Piggin
2007-01-31 6:06 ` Linus Torvalds
2007-01-31 8:43 ` Ingo Molnar
2007-01-31 20:13 ` Joel Becker
2007-01-31 18:20 ` Zach Brown
2007-01-31 17:47 ` Zach Brown
2007-01-31 17:38 ` Zach Brown
2007-01-31 17:51 ` Benjamin LaHaise
2007-01-31 19:25 ` Zach Brown
2007-01-31 20:05 ` Benjamin LaHaise
2007-01-31 20:41 ` Zach Brown
2007-02-04 5:13 ` Davide Libenzi
2007-02-04 20:00 ` Davide Libenzi
2007-02-09 22:33 ` Linus Torvalds
2007-02-09 23:11 ` Davide Libenzi
2007-02-09 23:35 ` Linus Torvalds
2007-02-10 18:45 ` Davide Libenzi
2007-02-10 19:01 ` Linus Torvalds
2007-02-10 19:35 ` Linus Torvalds
2007-02-10 20:59 ` Davide Libenzi
2007-02-10 0:04 ` Eric Dumazet
2007-02-10 0:12 ` Linus Torvalds
2007-02-10 0:34 ` Alan
2007-02-10 10:47 ` bert hubert
2007-02-10 18:19 ` Davide Libenzi
2007-02-11 0:56 ` David Miller
2007-02-11 2:49 ` Linus Torvalds
2007-02-14 16:42 ` James Antill
2007-02-03 14:05 [PATCH 2 of 4] Introduce i386 fibril scheduling linux
2007-02-06 13:43 Al Boldi
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