From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from protonic.prtnl (protonic.xs4all.nl [213.84.116.84]) by ozlabs.org (Postfix) with ESMTP id 155D4679F5 for ; Tue, 14 Mar 2006 18:50:13 +1100 (EST) From: David Jander To: linuxppc-embedded@ozlabs.org Subject: Re: Stable Linux kernel 2.6 for MPC8XX Date: Tue, 14 Mar 2006 08:50:46 +0100 References: <20060310153341.080163525CB@atlas.denx.de> In-Reply-To: <20060310153341.080163525CB@atlas.denx.de> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Message-Id: <200603140850.47014.david.jander@protonic.nl> List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Friday 10 March 2006 16:33, Wolfgang Denk wrote: > > I believe most of those observations and measurements are not valid > > anymore. Kernel 2.6 for 8xx has come a long way since this article was > > written. It might have been true back then, but it surely isn't anymore. > > So did you actually run any benchmarks? Specilations on what might be > or should be are not really helpful. Of course I did. Otherwise I wouldn't say this. Here's some benchmark data from nbench (sorry didn't try lmbench yet): The same ELDK (version 3.1.1) for both kernels, running on exactly the same board (MPC852T 100MHz, with 32Mbyte SDRAM and 32Mbyte Flash running from NFS root). I removed some FPU benchmarks, as they are pretty meaningless for this board and take an ethernity otherwise. Results for Kernel 2.4.25 (Denx CVS from around sept-oct or so, 2005): TEST : Iterations/sec. : Old Index : New Index : : Pentium 90* : AMD K6/233* --------------------:------------------:-------------:------------ NUMERIC SORT : 30.438 : 0.78 : 0.26 STRING SORT : 1.5842 : 0.71 : 0.11 BITFIELD : 7.9506e+06 : 1.36 : 0.28 FP EMULATION : 3.258 : 1.56 : 0.36 IDEA : 108.89 : 1.67 : 0.49 HUFFMAN : 26.281 : 0.73 : 0.23 LU DECOMPOSITION : 0.32765 : 0.02 : 0.01 ==========================ORIGINAL BYTEMARK RESULTS========================== INTEGER INDEX : 1.052 FLOATING-POINT INDEX: 0.257 Now the results for 2.6.14 (Denx git released 2.6.14): TEST : Iterations/sec. : Old Index : New Index : : Pentium 90* : AMD K6/233* --------------------:------------------:-------------:------------ NUMERIC SORT : 32.654 : 0.84 : 0.28 STRING SORT : 1.7408 : 0.78 : 0.12 BITFIELD : 8.3466e+06 : 1.43 : 0.30 FP EMULATION : 3.506 : 1.68 : 0.39 IDEA : 115.3 : 1.76 : 0.52 HUFFMAN : 27.855 : 0.77 : 0.25 LU DECOMPOSITION : 0.35932 : 0.02 : 0.01 ==========================ORIGINAL BYTEMARK RESULTS========================== INTEGER INDEX : 1.115 FLOATING-POINT INDEX: 0.265 I don't know why, but while everyone still says 2.6 is slower, I am consistently getting results that seem to prove the opposite. Why? Is the TLB/cache stuff better optimized for 8xx in 2.6? IMHO it is quite a difference. Btw, I also wrote different small "speed-measurement" tools (to measure loop-speed, memory throughput for different block sizes, etc...) and they all show aproximately the same increase. I was careful to strip both kernels of all unnecessary drivers and features that could hamper performance. If you wish I could try to dig up the .config files for you, but I am not sure I'll find them anymore (I did this when 2.6.14 was just released). Greetings, -- David Jander Protonic Holland.