From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: Hardware assisted parity computation - is it now worth it? Date: Mon, 17 Jul 2006 14:05:21 -0400 Message-ID: <44BBD161.5030609@tmr.com> References: <1152778739.26511.65.camel@swtf.comptex.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1152778739.26511.65.camel@swtf.comptex.com.au> Sender: linux-raid-owner@vger.kernel.org To: Burn Alting Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Burn Alting wrote: >Last year, there were discussions on this list about the possible >use of a 'co-processor' (Intel's IOP333) to compute raid 5/6's >parity data. > >We are about to see low cost, multi core cpu chips with very >high speed memory bandwidth. In light of this, is there any >effective benefit to such devices as the IOP333? > > Was there ever? Unless you're running on a really slow CPU, like 386, with a TB of RAID attached, and heavy CPU load, could anyone ever see a measureable performance gain? I haven't seen any such benchmarks, although I haven't looked beyond reading several related mailing lists. >Or in other words, is a cheaper (power, heat, etc) cpu with >higher memory access speeds, more cost effective than a >bridge/bus device (ie hardware) solution (which typically >has much lower memory access speeds)? > An additional device is always more complex, and less tunable than a CPU based solution. Except in the case above where there is very little CPU available, I don't see much hope for a cost (money and complexity) effective non-CPU solution. Obviously my opinion only. -- bill davidsen CTO TMR Associates, Inc Doing interesting things with small computers since 1979