From: Christoph Hellwig <hch@infradead.org>
To: NeilBrown <neilb@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>,
Dave Chinner <david@fromorbit.com>,
Nikolai Grigoriev <ngrigoriev@gmail.com>,
linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-raid@vger.kernel.org, linux-mm@kvack.org,
Jens Axboe <axboe@kernel.dk>
Subject: Re: ext4 vs btrfs performance on SSD array
Date: Fri, 5 Sep 2014 09:08:08 -0700 [thread overview]
Message-ID: <20140905160808.GA7967@infradead.org> (raw)
In-Reply-To: <20140903100158.34916d34@notabene.brown>
On Wed, Sep 03, 2014 at 10:01:58AM +1000, NeilBrown wrote:
> Do we still need maximums at all?
I don't think we do. At least on any system I work with I have to
increase them to get good performance without any adverse effect on
throttling.
> So can we just remove the limit on max_sectors and the RAID5 stripe cache
> size? I'm certainly keen to remove the later and just use a mempool if the
> limit isn't needed.
> I have seen reports that a very large raid5 stripe cache size can cause
> a reduction in performance. I don't know why but I suspect it is a bug that
> should be found and fixed.
>
> Do we need max_sectors ??
I'll send a patch to remove it and watch for the fireworks..
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: NeilBrown <neilb@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>,
Dave Chinner <david@fromorbit.com>,
Nikolai Grigoriev <ngrigoriev@gmail.com>,
linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-raid@vger.kernel.org, linux-mm@kvack.org,
Jens Axboe <axboe@kernel.dk>
Subject: Re: ext4 vs btrfs performance on SSD array
Date: Fri, 5 Sep 2014 09:08:08 -0700 [thread overview]
Message-ID: <20140905160808.GA7967@infradead.org> (raw)
In-Reply-To: <20140903100158.34916d34@notabene.brown>
On Wed, Sep 03, 2014 at 10:01:58AM +1000, NeilBrown wrote:
> Do we still need maximums at all?
I don't think we do. At least on any system I work with I have to
increase them to get good performance without any adverse effect on
throttling.
> So can we just remove the limit on max_sectors and the RAID5 stripe cache
> size? I'm certainly keen to remove the later and just use a mempool if the
> limit isn't needed.
> I have seen reports that a very large raid5 stripe cache size can cause
> a reduction in performance. I don't know why but I suspect it is a bug that
> should be found and fixed.
>
> Do we need max_sectors ??
I'll send a patch to remove it and watch for the fireworks..
--
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next prev parent reply other threads:[~2014-09-05 16:08 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-26 23:39 ext4 vs btrfs performance on SSD array Nikolai Grigoriev
2014-08-27 7:10 ` Duncan
2014-08-27 21:59 ` Nikolai Grigoriev
2014-09-02 0:08 ` Dave Chinner
2014-09-02 1:22 ` Christoph Hellwig
2014-09-02 1:22 ` Christoph Hellwig
2014-09-02 10:39 ` Zack Coffey
2014-09-02 11:31 ` Theodore Ts'o
2014-09-02 11:31 ` Theodore Ts'o
2014-09-02 14:20 ` Jan Kara
2014-09-02 14:20 ` Jan Kara
2014-09-02 14:55 ` Theodore Ts'o
2014-09-02 14:55 ` Theodore Ts'o
2014-09-02 12:55 ` Zack Coffey
2014-09-02 12:55 ` Zack Coffey
2014-09-02 13:40 ` Austin S Hemmelgarn
2014-09-03 0:01 ` NeilBrown
2014-09-05 16:08 ` Christoph Hellwig [this message]
2014-09-05 16:08 ` Christoph Hellwig
2014-09-05 16:40 ` Jeff Moyer
2014-09-05 16:40 ` Jeff Moyer
2014-09-05 16:50 ` Jens Axboe
2014-09-05 16:50 ` Jens Axboe
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