From: NeilBrown <neilb@suse.de>
To: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>,
Li Shaohua <shli@fusionio.com>, Theodore Ts'o <tytso@mit.edu>,
Marti Raudsepp <marti@juffo.org>,
Kernel hackers <linux-kernel@vger.kernel.org>,
ext4 hackers <linux-ext4@vger.kernel.org>,
maze@google.com, "Shi, Alex" <alex.shi@intel.com>,
linux-fsdevel@vger.kernel.org,
linux RAID <linux-raid@vger.kernel.org>
Subject: Re: ext4 write performance regression in 3.6-rc1 on RAID0/5
Date: Wed, 22 Aug 2012 16:00:25 +1000 [thread overview]
Message-ID: <20120822160025.272188d1@notabene.brown> (raw)
In-Reply-To: <20120822035702.GF2570@yliu-dev.sh.intel.com>
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On Wed, 22 Aug 2012 11:57:02 +0800 Yuanhan Liu <yuanhan.liu@linux.intel.com>
wrote:
>
> -#define NR_STRIPES 256
> +#define NR_STRIPES 1024
Changing one magic number into another magic number might help your case, but
it not really a general solution.
Possibly making sure that max_nr_stripes is at least some multiple of the
chunk size might make sense, but I wouldn't want to see a very large multiple.
I thing the problems with RAID5 are deeper than that. Hopefully I'll figure
out exactly what the best fix is soon - I'm trying to look into it.
I don't think the size of the cache is a big part of the solution. I think
correct scheduling of IO is the real answer.
Thanks,
NeilBrown
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next prev parent reply other threads:[~2012-08-22 6:00 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-15 18:33 NULL pointer dereference in ext4_ext_remove_space on 3.5.1 Marti Raudsepp
2012-08-16 2:46 ` Theodore Ts'o
2012-08-16 11:10 ` Fengguang Wu
2012-08-16 15:25 ` Theodore Ts'o
2012-08-16 20:21 ` Maciej Żenczykowski
2012-08-16 20:21 ` Maciej Żenczykowski
2012-08-16 21:19 ` Theodore Ts'o
2012-08-16 21:19 ` Theodore Ts'o
2012-08-16 21:40 ` Maciej Żenczykowski
2012-08-16 22:26 ` Theodore Ts'o
2012-08-16 22:44 ` Maciej Żenczykowski
2012-08-17 6:01 ` Fengguang Wu
2012-08-17 13:15 ` Theodore Ts'o
2012-08-17 13:22 ` Fengguang Wu
2012-08-17 13:50 ` [PATCH] ext4: fix kernel BUG on large-scale rm -rf commands Theodore Ts'o
2012-08-17 17:48 ` NULL pointer dereference in ext4_ext_remove_space on 3.5.1 Christoph Hellwig
2012-08-17 20:34 ` Theodore Ts'o
2012-08-17 20:34 ` Theodore Ts'o
2012-08-17 21:05 ` Christoph Hellwig
2012-08-17 21:05 ` Christoph Hellwig
2012-08-17 22:55 ` Dave Chinner
2012-08-17 22:55 ` Dave Chinner
2012-08-17 23:11 ` Theodore Ts'o
2012-08-17 23:11 ` Theodore Ts'o
2012-08-17 6:09 ` ext4 write performance regression in 3.6-rc1 Fengguang Wu
2012-08-17 13:40 ` Theodore Ts'o
2012-08-17 14:13 ` Fengguang Wu
2012-08-17 14:25 ` ext4 write performance regression in 3.6-rc1 on RAID0/5 Fengguang Wu
[not found] ` <20120817151318.GA2341@localhost>
2012-08-17 15:37 ` Theodore Ts'o
2012-08-17 20:44 ` NeilBrown
2012-08-21 9:42 ` Fengguang Wu
2012-08-21 12:07 ` Fengguang Wu
[not found] ` <20120822035702.GF2570@yliu-dev.sh.intel.com>
2012-08-22 4:07 ` Shaohua Li
2012-08-22 5:39 ` Yuanhan Liu
2012-08-22 6:00 ` NeilBrown [this message]
2012-08-22 6:31 ` Yuanhan Liu
2012-08-22 7:14 ` Andreas Dilger
2012-08-22 20:47 ` Dan Williams
2012-08-22 21:59 ` NeilBrown
2012-09-17 12:21 ` NULL pointer dereference in ext4_ext_remove_space on 3.5.1 Dmitry Monakhov
2012-09-17 13:52 ` Theodore Ts'o
2012-09-17 14:48 ` Dmitry Monakhov
2012-08-16 9:00 ` Fengguang Wu
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