From: Vladislav Bolkhovitin <vst@vlnb.net>
To: Tomasz Chmielewski <mangoo@wpkg.org>
Cc: Bart Van Assche <bart.vanassche@gmail.com>,
linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
iscsitarget-devel@lists.sourceforge.net,
James Bottomley <James.Bottomley@hansenpartnership.com>,
scst-devel <scst-devel@lists.sourceforge.net>,
stgt@vger.kernel.org
Subject: Re: [Scst-devel] [ANNOUNCE]: Comparison of features sets between different SCSI targets (SCST, STGT, IET, LIO)
Date: Mon, 06 Apr 2009 20:55:11 +0400 [thread overview]
Message-ID: <49DA33EF.3020700@vlnb.net> (raw)
In-Reply-To: <49D9D9A0.40106@wpkg.org>
Tomasz Chmielewski, on 04/06/2009 02:29 PM wrote:
> Bart Van Assche schrieb:
>
>> Hello Tomasz,
>>
>> It would be great if you could publish the details of your setup and
>> the tests you have run, such that we are able to reproduce the tests
>> and analyze the results further.
>
> Here it is.
>
> The target is running Debian Lenny 64bit userspace on an Intel Celeron 2.93GHz CPU, 2 GB RAM.
>
> Initiator is running Debian Etch 64 bit userspace, open-iscsi 2.0-869, Intel Xeon 3050/2.13GHz, 8 GB RAM.
>
>
> Each test was repeated 6 times, "sync" was made and caches were dropped on both sides before each test was started.
>
> dd parameters were like below, so 6.6 GB of data was read each time:
>
> dd if=/dev/sdag of=/dev/null bs=64k count=100000
>
>
> Data was read from two block devices:
> - /dev/md0, which is RAID-1 on two ST31500341AS 1.5 TB drives
> - encrypted dm-crypt device which is on top of /dev/md0
>
> Encrypted device was created with the following additional options passed to cryptsetup
> (it provides the most performance on systems where CPU is a bottleneck, but with decreased
> security when compared to default options):
>
> -c aes-ecb-plain -s 128
>
>
> Generally, CPU on the target was a bottleneck, so I also tested the load on target.
>
>
> md0, crypt columns - averages from dd
> us, sy, id, wa - averages from vmstat
>
>
> 1. Disk speeds on the target
>
> Raw performance: 102.17 MB/s
> Raw performance (encrypted): 50.21 MB/s
>
>
> 2. Read-ahead on the initiator: 256 (default); md0, crypt - MB/s
>
> md0 us sy id wa | crypt us sy id wa
> STGT 50.63 4% 45% 18% 33% | 32.52 3% 62% 16% 19%
> SCST (debug + no patches) 43.75 0% 26% 30% 44% | 42.05 0% 84% 1% 15%
> SCST (fullperf + patches) 45.18 0% 25% 33% 42% | 44.12 0% 81% 2% 17%
>
>
> 3. Read-ahead on the initiator: 16384; md0, crypt - MB/s
>
> md0 us sy id wa | crypt us sy id wa
> STGT 56.43 3% 55% 2% 40% | 46.90 3% 90% 3% 4%
> SCST (debug + no patches) 73.85 0% 58% 1% 41% | 42.70 0% 85% 0% 15%
> SCST (fullperf + patches) 76.27 0% 63% 1% 36% | 42.52 0% 85% 0% 15%
Good! You proved that:
1. SCST is capable to work much better than STGT: 35% for md and 37% for
crypt considering maximum values.
2. Default read-ahead size isn't appropriate for remote data access
cases and should be increased. I slowly have been discussing it in past
few months with Wu Fengguang, the read-ahead maintainer.
Which IO scheduler on the target did you use? I guess, deadline? If so,
you should try with CFQ as well.
Thanks,
Vlad
next prev parent reply other threads:[~2009-04-06 16:55 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-04 18:56 [ANNOUNCE]: Comparison of features sets between different SCSI targets (SCST, STGT, IET, LIO) Vladislav Bolkhovitin
2009-04-04 19:12 ` [Scst-devel] " Tomasz Chmielewski
2009-04-04 19:21 ` Vladislav Bolkhovitin
2009-04-06 9:44 ` Tomasz Chmielewski
2009-04-05 11:29 ` Bart Van Assche
2009-04-06 10:29 ` Tomasz Chmielewski
2009-04-06 10:40 ` Tomasz Chmielewski
2009-04-06 16:55 ` Vladislav Bolkhovitin [this message]
2009-04-06 18:27 ` Tomasz Chmielewski
2009-04-07 20:27 ` Bart Van Assche
2009-04-09 18:45 ` Vladislav Bolkhovitin
2009-04-14 11:07 ` Tomasz Chmielewski
2009-04-14 18:10 ` Vladislav Bolkhovitin
2009-04-06 19:01 ` Bart Van Assche
2009-04-06 19:05 ` Tomasz Chmielewski
[not found] ` <c9a3e4540904052019o3c89128eq52d9046fef7e2725@mail.gmail.com>
2009-04-06 7:32 ` Vladislav Bolkhovitin
[not found] ` <c9a3e4540904060057w75b5525an9c63486ed00ca9a5@mail.gmail.com>
2009-04-06 12:21 ` Vladislav Bolkhovitin
[not found] ` <c9a3e4540904060319l3c885641k1217fba468f1fcf8@mail.gmail.com>
2009-04-06 17:57 ` Vladislav Bolkhovitin
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