From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp4.clb.oleane.net (smtp4.clb.oleane.net [213.56.31.20]) by ozlabs.org (Postfix) with ESMTP id 8F49868416 for ; Wed, 28 Sep 2005 17:59:59 +1000 (EST) From: =?iso-8859-1?Q?G=E9rard_Gu=E9vel?= To: "'Andy Fleming'" Date: Wed, 28 Sep 2005 10:02:18 +0200 Message-ID: <003201c5c402$fb80d430$5201a8c0@GEG2400> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" In-Reply-To: Cc: linuxppc-embedded@ozlabs.org Subject: RE: How to use SPE on MPC8541 List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Andy, > Your driver runs in kernel space. The kernel has the SPE bit off. > The MSR state is process-specific. If the code executes, the > MSR bit > is set. Why do you want to see if the bit is set? OK, this is a bad idea to use a driver to check the msr register. I don't especially want to see if the bit is set, I just want to improve the board performance for a Linux application :-). To check the performance, I used the Dhrystone 2.1 benchmark with the standard glibc (strcpy, strcmp, ...) on one part, and with the freescale SPE library on the other part (vstrcpy, vstrcmp, ...). I already verified in the binary elf file that the right functions are called. When I run the benchmark, I get the same MIPS with and without SPE code. I ran the same benchmark on the same board without OS, with a personal pseudo glibc, I have the same MIPS as under Linux, with the freescale library, I gain 40% of perf. That's I want to retreive with the Linux OS. Regards Gérard