From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wy0-f170.google.com (mail-wy0-f170.google.com [74.125.82.170]) by ozlabs.org (Postfix) with ESMTP id 4A990B7108 for ; Tue, 9 Nov 2010 03:01:05 +1100 (EST) Received: by wyb35 with SMTP id 35so7573722wyb.15 for ; Mon, 08 Nov 2010 08:01:03 -0800 (PST) MIME-Version: 1.0 Date: Mon, 8 Nov 2010 17:00:58 +0100 Message-ID: Subject: Better performance when CONFIG_DEBUG_KERNEL is on From: Jean-Michel Hautbois To: linuxppc-dev@ozlabs.org Content-Type: text/plain; charset=UTF-8 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi everybody, I am using a mpc5200 chip with a linux 2.6.33.7-rt29. I am using the ELDK toolchain : ppc_6xx-gcc -v Target: powerpc-linux Configured with: /opt/eldk/build/ppc-2008-04-01/work/usr/src/denx/BUILD/crosstool-0.43/build/gcc-4.2.2-glibc-20070515T2025-eldk/powerpc-linux/gcc-4.2.2/configure --target=powerpc-linux --host=i686-host_pc-linux-gnu --prefix=/var/tmp/eldk.UZpAG7/usr/crosstool/gcc-4.2.2-glibc-20070515T2025-eldk/powerpc-linux --disable-hosted-libstdcxx --with-headers=/var/tmp/eldk.UZpAG7/usr/crosstool/gcc-4.2.2-glibc-20070515T2025-eldk/powerpc-linux/powerpc-linux/include --with-local-prefix=/var/tmp/eldk.UZpAG7/usr/crosstool/gcc-4.2.2-glibc-20070515T2025-eldk/powerpc-linux/powerpc-linux --disable-nls --enable-threads=posix --enable-symvers=gnu --enable-__cxa_atexit --enable-languages=c,c++,java --enable-shared --enable-c99 --enable-long-long --without-x Thread model: posix gcc version 4.2.2 When I have the CONFIG_DEBUG_KERNEL flag, the latencies I am mesuring are better than when the flag is off. And the jitter is lower... I must tell I am confused. I have no explanation about that, except maybe optimisations which would be different when the -g flag is added... If any of you has an idea, I am looking forward for your response :). Thanks in advance, Best Regards. JM