From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: Performance of a software raid 5 Date: Wed, 22 Apr 2009 08:29:36 -0400 Message-ID: <49EF0DB0.6090800@tmr.com> References: <49ED096E.1000002@anonymous.org.uk> <49ED18E6.1090301@anonymous.org.uk> <15c92f8bd27d912e292c013fea2467e4.squirrel@neil.brown.name> <49EE16F7.8060406@fatooh.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <49EE16F7.8060406@fatooh.org> Sender: linux-raid-owner@vger.kernel.org To: Corey Hickey Cc: Johannes Segitz , linux-raid@vger.kernel.org List-Id: linux-raid.ids Corey Hickey wrote: > Johannes Segitz wrote: > >> On Tue, Apr 21, 2009 at 3:19 AM, NeilBrown wrote: >> >>> Have you done any testing without the crypto layer to see what effect >>> that has? >>> >>> Can I suggest: >>> >>> for d in /dev/sd[gjk]1 /dev/md6 /dev/mapper/data bigfile >>> do >>> dd if=$d of=/dev/null bs=1M count=100 >>> done >>> >>> and report the times. >>> >> tested it with 1gb instead of 100 mb >> >> sdg >> 1048576000 bytes (1.0 GB) copied, 9.89311 s, 106 MB/s >> sdj >> 1048576000 bytes (1.0 GB) copied, 10.094 s, 104 MB/s >> sdk >> 1048576000 bytes (1.0 GB) copied, 8.53513 s, 123 MB/s >> /dev/md6 >> 1048576000 bytes (1.0 GB) copied, 11.4741 s, 91.4 MB/s >> /dev/mapper/data >> 1048576000 bytes (1.0 GB) copied, 34.4544 s, 30.4 MB/s >> bigfile >> 1048576000 bytes (1.0 GB) copied, 26.6532 s, 39.3 MB/s >> >> so the crypto indeed slows it down (and i'm surprised that it's that >> bad because i've read >> it's not a big hit on current CPUs and the X2 isn't new but not that >> old) but still read speed >> from md6 is worse than from one drive alone >> > > If it helps, some recent dd benchmarks I did indicate that twofish is > about 25% faster than aes on my Athlon64. > > Athlon64 3400+ 2.4 GHz, 64-bit Linux 2.6.28.2 > > Both aes and twofish are using the asm implementations according to > /proc/crypto. > > All numbers are in MB/s; average of three tests for a 512MB dd > read/write to the encrypted device. > > read write > aes 69.4 61.0 > twofish 86.8 76.6 > aes-cbc-essiv:sha256 65.1 56.3 > twofish-cbc-essiv:sha256 82.6 73.5 > Good info, but was the CPU maxed or was something else the limiting factor? -- bill davidsen CTO TMR Associates, Inc "You are disgraced professional losers. And by the way, give us our money back." - Representative Earl Pomeroy, Democrat of North Dakota on the A.I.G. executives who were paid bonuses after a federal bailout.