From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261563AbUHNMnU (ORCPT ); Sat, 14 Aug 2004 08:43:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261451AbUHNMnT (ORCPT ); Sat, 14 Aug 2004 08:43:19 -0400 Received: from colin2.muc.de ([193.149.48.15]:32517 "HELO colin2.muc.de") by vger.kernel.org with SMTP id S261563AbUHNMlr (ORCPT ); Sat, 14 Aug 2004 08:41:47 -0400 Date: 14 Aug 2004 14:41:45 +0200 Date: Sat, 14 Aug 2004 14:41:45 +0200 From: Andi Kleen To: Paulo Marques Cc: Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [patch] Latency Tracer, voluntary-preempt-2.6.8-rc4-O6 Message-ID: <20040814124145.GA96097@muc.de> References: <2rfT9-5wi-17@gated-at.bofh.it> <2rF1c-6Iy-7@gated-at.bofh.it> <2sxEs-46P-1@gated-at.bofh.it> <2sCkH-7i5-15@gated-at.bofh.it> <2sHu9-2EW-31@gated-at.bofh.it> <20040813121502.GA18860@elte.hu> <20040813121800.GA68967@muc.de> <20040813135109.GA20638@elte.hu> <411D9A2A.1000202@grupopie.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <411D9A2A.1000202@grupopie.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > The final algorithm pre-calculates markers on the compressed symbols so > that the search time is almost divided by the number of markers. You could do that at compile time (in scripts/kallsyms.c) > > There are still a few issues with this approach. The biggest issue is > that this is clearly a speed/space trade-off, and maybe we don't want to > waste the space on a code path that is not supposed to be "hot". If this > is the case, I can make a smaller patch, that fixes just the name > "decompression" strcpy's. I'm surprised that using 8 markers helps anything. There should be many many more 0 stems than that in a not so big kernel. Did you actually measure the hit rate of the cache? I bet it is pretty low. -Andi