From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24852 invoked by alias); 23 Oct 2006 20:36:00 -0000 Received: (qmail 24799 invoked by uid 22791); 23 Oct 2006 20:35:59 -0000 X-Spam-Status: No, hits=-2.7 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (66.187.233.31) by sourceware.org (qpsmtpd/0.31) with ESMTP; Mon, 23 Oct 2006 20:35:54 +0000 Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254]) by mx1.redhat.com (8.12.11.20060308/8.12.11) with ESMTP id k9NKZr8A028581; Mon, 23 Oct 2006 16:35:53 -0400 Received: from pobox.hsv.redhat.com (pobox.hsv.redhat.com [172.16.16.12]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id k9NKZpSx031172; Mon, 23 Oct 2006 16:35:52 -0400 Received: from [172.16.17.170] (dhcp-170.hsv.redhat.com [172.16.17.170]) by pobox.hsv.redhat.com (8.12.11.20060308/8.12.11) with ESMTP id k9NKZnRN029542; Mon, 23 Oct 2006 16:35:50 -0400 Message-ID: <453D27A8.3050407@redhat.com> Date: Mon, 23 Oct 2006 20:36:00 -0000 From: David Smith User-Agent: Thunderbird 1.5.0.7 (X11/20061004) MIME-Version: 1.0 To: "Frank Ch. Eigler" CC: systemtap@sources.redhat.com Subject: Re: precompiled probing scenarios References: <453922E8.4000608@redhat.com> <20061020193244.GC17981@elastic.org> <4539288E.7040104@redhat.com> <20061020201318.GD17981@elastic.org> In-Reply-To: <20061020201318.GD17981@elastic.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2006-q4/txt/msg00236.txt.bz2 Frank Ch. Eigler wrote: > Hi - > > dsmith wrote: >> [...] >> I don't hash the getuid(), since: >> - by default your cache is stored in your home directory >> - who you are doesn't change the pass 2-4 output > > That's all true. One possible reason for including getuid() anyway is > so that two different sudo-empowered people can run the same script at > the same time without one having to disable his cache. Ah - makes sense, I've added this. >> Nope. I actually cache the module and the C file so I can skip pass 3 >> but still preserve semantics. > > OK. > >> Hmm. How about something like: >> Pass 3: Using cached >> /home/dsmith/.stap_cache/d/8/stap_d833fd040735ddde57a23bebb4456542_201.c >> Pass 4: Using cached >> /home/dsmith/.stap_cache/d/8/stap_d833fd040735ddde57a23bebb4456542_201.ko > > Works for me. OK, I've implemented this. > (It may be a worthwhile minor simplification to use > one-byte /d8/ as a partitioning subdirectory rather than two-nibble > /d/8/ scheme. 256 files in a single directory are well handled in our > filesystems.) I did it this way because ccache did it this way. My sense is that it was done this way to make sure the directories with cached files didn't end up too large (not the partition directories themselves). Of course ccache's problem is a bit worse than ours - they cache 3 files for every .o file (the .o file itself, gcc stdout, and gcc stderr) while we only cache 2 files per ,ko (the .ko itself and the associated .c file). (Also note that the number of levels is configurable. The default is 2, but setting the SYSTEMTAP_NLEVELS environment variable lets you set it from 1 to 8.) -- David Smith dsmith@redhat.com Red Hat http://www.redhat.com 256.217.0141 (direct) 256.837.0057 (fax)