From: Hans Reiser <reiser@namesys.com>
To: William Lee Irwin III <wli@holomorphy.com>
Cc: Lee Revell <rlrevell@joe-job.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>, Robert Love <rml@ximian.com>,
Andrea Arcangeli <andrea@novell.com>,
Nick Piggin <nickpiggin@yahoo.com.au>,
Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@osdl.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [patch] sched: fix scheduling latencies for !PREEMPT kernels
Date: Wed, 15 Sep 2004 06:36:24 -0700 [thread overview]
Message-ID: <41484558.6060301@namesys.com> (raw)
In-Reply-To: <20040915023611.GH9106@holomorphy.com>
William Lee Irwin III wrote:
>On Tue, 2004-09-14 at 21:46, William Lee Irwin III wrote:
>
>
>>>I've not heard a peep about anyone trying to fix this. It should be
>>>killed off along with the rest, of course, but like I said before, it's
>>>the messiest, dirtiest, and ugliest code that's left to go through,
>>>which is why it's been left for last. e.g. driver ->ioctl() methods.
>>>
>>>
>
>On Tue, Sep 14, 2004 at 10:00:44PM -0400, Lee Revell wrote:
>
>
>>Andrew tried to fix this a few times in 2.4 and it broke the FS in
>>subtle ways. Don't have an archive link but the message is
>><20040712163141.31ef1ad6.akpm@osdl.org>. I asked Hans directly about it
>>and he said "balancing makes it hard, the fix is reiser4", see
>><411925FA.2000303@namesys.com>.
>>
>>
>
>I have neither of these locally. I suspect someone needs to care enough
>about the code for anything to happen soon. I suppose there are things
>that probably weren't tried, e.g. auditing to make sure dependencies on
>external synchronization are taken care of, removing implicit sleeping
>with the BKL held, then punt a private recursive spinlock in reiser3's
>direction. Not sure what went on, or if I want to get involved in this
>particular case.
>
>
>-- wli
>-
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>
>
>
>
Why bother? It is V3, it should be left undisturbed except for
bugfixes. Please, spend your efforts on reducing V4 latency and
measuring whether it fails to scale to multiple processors. That would
be very useful to me if someone helped with that. V4 has the
architecture for doing such things well, but there are always accidental
bottlenecks that testing can discover, and I am sure we will have a
handful of things preventing us from scaling well that are not hard to
fix. It would be nice to fix those......
The hard stuff for scalability, the locking of the tree, we did that.
We just haven't tested and evaluated and refined like we need to in V4.
Hans
next prev parent reply other threads:[~2004-09-15 13:39 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-14 9:15 [patch] preempt-cleanup.patch, 2.6.9-rc2 Ingo Molnar
2004-09-14 9:34 ` [printk] make console_conditional_schedule() __sched and use cond_resched() William Lee Irwin III
2004-09-14 9:38 ` [patch] preempt-lock-need-resched.patch, 2.6.9-rc2 Ingo Molnar
2004-09-14 9:51 ` [patch] sched: add cond_resched_softirq() Ingo Molnar
2004-09-14 9:57 ` [patch] sched: fix latency in random driver Ingo Molnar
2004-09-14 10:06 ` [patch] sched, ext3: fix scheduling latencies in ext3 Ingo Molnar
2004-09-14 10:13 ` [patch] sched, vfs: fix scheduling latencies in invalidate_inodes() Ingo Molnar
2004-09-14 10:19 ` [patch] sched, vfs: fix scheduling latencies in prune_dcache() and select_parent() Ingo Molnar
2004-09-14 10:25 ` [patch] sched, net: fix scheduling latencies in netstat Ingo Molnar
2004-09-14 10:44 ` [patch] sched, net: fix scheduling latencies in __release_sock Ingo Molnar
2004-09-14 10:50 ` [patch] sched, mm: fix scheduling latencies in copy_page_range() Ingo Molnar
2004-09-14 10:56 ` [patch] sched, mm: fix scheduling latencies in unmap_vmas() Ingo Molnar
2004-09-14 10:59 ` [patch] sched, mm: fix scheduling latencies in get_user_pages() Ingo Molnar
2004-09-14 11:02 ` [patch] sched, mm: fix scheduling latencies in filemap_sync() Ingo Molnar
2004-09-14 11:06 ` [patch] sched, tty: fix scheduling latencies in tty_io.c Ingo Molnar
2004-09-14 10:53 ` Alan Cox
2004-09-14 12:00 ` Ingo Molnar
2004-09-14 11:18 ` Alan Cox
2004-09-14 12:27 ` Ingo Molnar
2004-09-14 12:11 ` Alan Cox
2004-09-14 11:08 ` [patch] sched, pty: fix scheduling latencies in pty.c Ingo Molnar
2004-09-14 11:12 ` [patch] might_sleep() additions to fs-writeback.c Ingo Molnar
2004-09-14 11:25 ` [patch] fix keventd execution dependency Ingo Molnar
2004-09-15 22:18 ` Rusty Russell
2004-09-14 11:28 ` [patch] sched: fix scheduling latencies in mttr.c Ingo Molnar
2004-09-14 11:32 ` [patch] sched: fix scheduling latencies in vgacon.c Ingo Molnar
2004-09-14 11:35 ` [patch] sched: fix scheduling latencies in NTFS mount Ingo Molnar
2004-09-14 13:31 ` Anton Altaparmakov
2004-09-14 11:42 ` [patch] sched: fix scheduling latencies for !PREEMPT kernels Ingo Molnar
2004-09-14 12:55 ` Nick Piggin
2004-09-14 13:22 ` Ingo Molnar
2004-09-14 13:33 ` Nick Piggin
2004-09-14 14:09 ` Andrea Arcangeli
2004-09-14 14:28 ` Nick Piggin
2004-09-14 15:03 ` Andrea Arcangeli
2004-09-14 18:05 ` Robert Love
2004-09-14 18:52 ` William Lee Irwin III
2004-09-14 19:02 ` Robert Love
2004-09-14 19:21 ` William Lee Irwin III
2004-09-14 19:19 ` Alan Cox
2004-09-15 0:22 ` Lee Revell
2004-09-15 1:46 ` William Lee Irwin III
2004-09-15 2:00 ` Lee Revell
2004-09-15 2:36 ` William Lee Irwin III
2004-09-15 2:59 ` Lee Revell
2004-09-15 13:36 ` Hans Reiser [this message]
2004-09-15 20:40 ` William Lee Irwin III
2004-09-15 1:18 ` William Lee Irwin III
2004-09-14 19:26 ` Robert Love
2004-09-14 21:06 ` William Lee Irwin III
2004-09-14 19:25 ` Andrea Arcangeli
2004-09-14 19:29 ` Robert Love
2004-09-14 19:34 ` William Lee Irwin III
2004-09-15 1:02 ` Lee Revell
2004-09-15 1:39 ` William Lee Irwin III
2004-09-15 2:11 ` Lee Revell
2004-09-15 11:17 ` Ingo Molnar
2004-09-15 9:56 ` Ingo Molnar
2004-09-15 9:57 ` William Lee Irwin III
2004-09-15 10:12 ` Ingo Molnar
2004-09-14 16:31 ` William Lee Irwin III
2004-09-14 16:39 ` Andrea Arcangeli
2004-09-14 14:54 ` Ingo Molnar
2004-09-14 22:55 ` Nick Piggin
2004-09-15 6:19 ` Ingo Molnar
2004-09-15 8:23 ` Nick Piggin
2004-09-15 8:43 ` Ingo Molnar
2004-09-15 10:09 ` William Lee Irwin III
2004-09-15 10:21 ` Ingo Molnar
2004-09-16 1:03 ` Nick Piggin
2004-09-16 6:14 ` Ingo Molnar
2004-09-15 0:35 ` Lee Revell
2004-09-14 13:25 ` [patch] sched: fix scheduling latencies in mtrr.c Ingo Molnar
2004-09-14 13:15 ` Alan Cox
2004-09-14 15:00 ` Ingo Molnar
2004-09-14 18:22 ` Zwane Mwaikambo
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