From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Mark Nelson To: Arnd Bergmann Subject: Re: [RFC 0/3] powerpc: memory copy routines tweaked for Cell Date: Fri, 20 Jun 2008 09:49:29 +1000 References: <200806191753.51495.markn@au1.ibm.com> <200806191353.17323.arnd@arndb.de> In-Reply-To: <200806191353.17323.arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Message-Id: <200806200949.29673.markn@au1.ibm.com> Cc: linuxppc-dev@ozlabs.org, Gunnar von Boehn , cbe-oss-dev@ozlabs.org, Michael Ellerman List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 19 Jun 2008 09:53:16 pm Arnd Bergmann wrote: > On Thursday 19 June 2008, Mark Nelson wrote: > > The plan is to use Michael Ellerman's code patching work so that at runtime > > if we're running on a Cell machine the new routines are called but otherwise > > the existing memory copy routines are used. > > Have you tried running this code on other platforms to see if it > actually performs worse on any of them? I would guess that the > older code also doesn't work too well on Power 5 and Power 6, so the > cell optimized version could give us a significant advantage as well, > albeit less than another CPU specific version. > > Arnd <>< > I did run the tests on Power 5 and Power 6, and on Power 5 with the new routines, the iperf bandwidth increased to 7.9 GBits/sec up from 7.5 GBits/sec; but on Power 6 the bandwidth with the old routines was 13.6 GBits/sec compared to 12.8 GBits/sec... I also couldn't get the updated routines to boot on 970MP without removing the dcbz instructions. I'll investigate more and also rerun the tests again Thanks! Mark