From: "Stephen C. Tweedie" <sct@redhat.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Mingming Cao <cmm@us.ibm.com>, Lee Revell <rlrevell@joe-job.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>, Stephen Tweedie <sct@redhat.com>
Subject: Re: ext3 allocate-with-reservation latencies
Date: Thu, 07 Apr 2005 14:08:24 +0100 [thread overview]
Message-ID: <1112879303.2859.78.camel@sisko.sctweedie.blueyonder.co.uk> (raw)
In-Reply-To: <20050407081434.GA28008@elte.hu>
Hi,
On Thu, 2005-04-07 at 09:14, Ingo Molnar wrote:
> doesnt the first option also allow searches to be in parallel?
In terms of CPU usage, yes. But either we use large windows, in which
case we *can't* search remotely near areas of the disk in parallel; or
we use small windows, in which case failure to find a free bit becomes
disproportionately expensive (we have to do an rbtree link and unlink
for each window we search.)
> This
> particular one took over 1 msec, so it seems there's a fair room for
> parallellizing multiple writers and thus improving scalability. (or is
> this codepath serialized globally anyway?)
No, the rbtree ops are serialised per-sb, and allocations within any one
inode are serialised, but the bitmap searches need not be serialised
globally. (They are in the case of new window searches right now, which
is what we're trying to fix.)
--Stephen
next prev parent reply other threads:[~2005-04-07 13:09 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-05 3:51 ext3 allocate-with-reservation latencies Lee Revell
2005-04-05 4:13 ` Ingo Molnar
2005-04-05 6:10 ` Mingming Cao
2005-04-05 16:38 ` Lee Revell
2005-04-06 5:35 ` Mingming Cao
2005-04-06 9:51 ` Stephen C. Tweedie
2005-04-06 16:53 ` Mingming Cao
2005-04-06 18:22 ` Stephen C. Tweedie
2005-04-06 19:03 ` Mingming Cao
2005-04-07 8:14 ` Ingo Molnar
2005-04-07 13:08 ` Stephen C. Tweedie [this message]
2005-04-07 19:16 ` Mingming Cao
2005-04-07 23:37 ` Mingming Cao
2005-04-08 14:40 ` Stephen C. Tweedie
2005-04-08 16:06 ` Arjan van de Ven
2005-04-08 18:10 ` Mingming Cao
2005-04-08 18:12 ` Lee Revell
2005-04-11 11:48 ` Stephen C. Tweedie
2005-04-11 18:38 ` Mingming Cao
2005-04-11 19:12 ` Lee Revell
2005-04-11 19:22 ` Lee Revell
2005-04-11 19:57 ` Stephen C. Tweedie
2005-04-12 6:41 ` Mingming Cao
2005-04-12 11:18 ` Stephen C. Tweedie
2005-04-12 23:27 ` Mingming Cao
2005-04-13 10:29 ` Stephen C. Tweedie
[not found] ` <1113597161.3899.80.camel@localhost.localdomain>
2005-04-18 18:00 ` Stephen C. Tweedie
2005-04-18 21:56 ` [Ext2-devel] " Mingming Cao
2005-04-22 22:10 ` [RFC][PATCH] Reduce ext3 allocate-with-reservation lock latencies Mingming Cao
2005-04-28 3:45 ` Lee Revell
2005-04-28 7:37 ` Mingming Cao
2005-04-28 16:12 ` Lee Revell
2005-04-28 18:34 ` Mingming Cao
2005-04-29 6:18 ` Mingming Cao
2005-04-28 19:14 ` [RFC] Adding multiple block allocation to current ext3 Mingming Cao
2005-04-29 13:52 ` [Ext2-devel] [RFC] Adding multiple block allocation Suparna Bhattacharya
2005-04-29 17:10 ` Mingming Cao
2005-04-29 19:42 ` Mingming Cao
2005-04-29 20:57 ` Andrew Morton
2005-04-29 21:12 ` Mingming Cao
2005-04-29 21:34 ` Andrew Morton
2005-04-30 16:00 ` Suparna Bhattacharya
2005-04-29 18:45 ` Badari Pulavarty
2005-04-29 23:22 ` Mingming Cao
2005-04-30 16:10 ` Suparna Bhattacharya
2005-04-30 17:11 ` Suparna Bhattacharya
2005-04-30 18:07 ` Mingming Cao
2005-05-02 4:46 ` Suparna Bhattacharya
2005-04-30 16:52 ` Suparna Bhattacharya
2005-04-30 0:33 ` Mingming Cao
2005-04-30 0:44 ` Mingming Cao
2005-04-30 17:03 ` Suparna Bhattacharya
2006-01-10 23:26 ` [PATCH 0/5] multiple block allocation to current ext3 Mingming Cao
2006-01-11 5:25 ` Andrew Morton
2006-01-11 19:17 ` Mingming Cao
2006-01-11 19:43 ` Andrew Morton
2006-01-11 21:31 ` Mingming Cao
2006-01-14 1:12 ` Fall back io scheduler for 2.6.15? Mingming Cao
2006-01-14 1:49 ` Andrew Morton
2006-01-14 5:22 ` Dave Jones
2006-01-16 8:43 ` Jens Axboe
2006-01-16 19:45 ` [PATCH] Fall back io scheduler ( Re: [Ext2-devel] Re: Fall back io scheduler for 2.6.15?) Mingming Cao
2006-01-16 19:49 ` Jens Axboe
2006-01-16 19:57 ` Mingming Cao
2006-01-19 19:37 ` Fall back io scheduler for 2.6.15? Nate Diller
2006-01-20 8:10 ` Jens Axboe
2006-01-16 19:38 ` [Ext2-devel] " Mingming Cao
2005-04-29 6:28 ` [PATCH] Reduce ext3 allocate-with-reservation lock latencies Mingming Cao
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