From: NeilBrown <neilb@suse.de>
To: Pedro Teixeira <finas@aeiou.pt>
Cc: linux-raid@vger.kernel.org
Subject: Re: Raid10 multi core scaling
Date: Mon, 2 Dec 2013 17:22:07 +1100 [thread overview]
Message-ID: <20131202172207.7400e03a@notabene.brown> (raw)
In-Reply-To: <20131126105859.Horde.-ppIIPYRo99SlH7zGogGx_A@webmail.aeiou.pt>
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On Tue, 26 Nov 2013 10:58:59 +0000 Pedro Teixeira <finas@aeiou.pt> wrote:
> I created a Raid10 array with 16 sata 1TB disks and the array
> performance
> seems to be limited by the md0_raid10 taking 99% of one core and not
> scalling to other cores. I tried overclocing the cpu cores and this lead to
> a small increase in performance ( but md0_raid10 keeps eating 99% of one
> core ).
Are you really talking about general array performance, or just resync
performance?
Because md0_raid10 doesn't do much work for normal IO so that should scale to
multiple processors.
I'm not sure that optimising resync to use more than one processor is really
much of a priority - is it?
NeilBrown
>
> I'm using:
> - a phenom X6 at 3600mhz
> - 16 seagate SSHDs ( sata3 7200RPM with 8GB ssd cache )
> - 4x marvell 9230 sata3 controllers ( 4 ports each ) pcie 2.0 2x
> lanes.
> - 8GB ram
> - custom 3.12 kernel and mdadm compiled from latest source
>
> what I did to test performance was to force a check on the array, and
> this
> leads to mdadm reporting a speed of about 990000K/sec. The hard disks
> report a 54% utilization. ( Overclocking the cpu by 200mhz increases the
> resync speed a bit and the hdd's utilizartion to about 58% )
>
> If I do the same with a raid5 array instead of raid10, them resync
> speed
> will be almost double of raid10, the harddisk utilization reported will be
> 98-100% and I can see at least two cores being used.
>
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next prev parent reply other threads:[~2013-12-02 6:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-26 10:58 Raid10 multi core scaling Pedro Teixeira
2013-11-26 11:19 ` Adam Goryachev
2013-11-27 6:52 ` Stan Hoeppner
2013-12-02 6:22 ` NeilBrown [this message]
2013-12-02 8:19 ` David Brown
2013-12-02 9:04 ` NeilBrown
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