From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaldo Carvalho de Melo Subject: Re: perf buildid-cache -p question Date: Mon, 16 Oct 2017 11:12:22 -0300 Message-ID: <20171016141222.GC5311@kernel.org> References: <8594e11c-9aa1-f600-3f04-eb80058c9abf@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail.kernel.org ([198.145.29.99]:44620 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752151AbdJPOMZ (ORCPT ); Mon, 16 Oct 2017 10:12:25 -0400 Content-Disposition: inline In-Reply-To: <8594e11c-9aa1-f600-3f04-eb80058c9abf@linux.vnet.ibm.com> Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Thomas-Mich Richter Cc: "linux-perf-use." , Hendrik Brueckner , Masami Hiramatsu Em Mon, Oct 16, 2017 at 02:24:11PM +0200, Thomas-Mich Richter escreveu: > Maybe its me misunderstanding the buildid cache completely, but I ran into the following issue: > > I can add and remove files using the perf buildid-cache command. For example > perf buildid-cache -a /usr/bin/tar adds the tar executable to the buildid-cache directory > .debug/usr/bin/tar > and creates the subdirectory > .debug/usr/bin/tar/e54c9946802bbbcb85760ffeb80700a5fd35ebe7/elf file. That is correct. > Also a symbolic link from the directory > .debug/.buildid/e5/4c9946802bbbcb85760ffeb80700a5fd35ebe7 --> ../../usr/bin/tar// > is created. > > Command perf buildid-cache -a /usr/bin/tar Nope, command 'perf buildid-cache -r /usr/bin/tar' does it: [root@jouet ~]# ls -la ~/.debug/usr/bin/tar/4c10f253c0cb8459dd846235c0bc18929e4758ea [root@jouet ~]# ls -la ~/.debug/.build-id/4c/10f253c0cb8459dd846235c0bc18929e4758ea lrwxrwxrwx. 1 root root 58 Oct 16 10:50 /root/.debug/.build-id/4c/10f253c0cb8459dd846235c0bc18929e4758ea -> ../../usr/bin/tar/4c10f253c0cb8459dd846235c0bc18929e4758ea [root@jouet ~]# [root@jouet ~]# perf buildid-cache -r /usr/bin/tar [root@jouet ~]# ls -la ~/.debug/usr/bin/tar/4c10f253c0cb8459dd846235c0bc18929e4758ea ls: cannot access '/root/.debug/usr/bin/tar/4c10f253c0cb8459dd846235c0bc18929e4758ea': No such file or directory [root@jouet ~]# ls -la ~/.debug/.build-id/4c/10f253c0cb8459dd846235c0bc18929e4758ea ls: cannot access '/root/.debug/.build-id/4c/10f253c0cb8459dd846235c0bc18929e4758ea': No such file or directory [root@jouet ~]# > removes these entries. > > Now when I run ./perf buildid-cache -p /usr/bin > nothing happens and success is reported: When you do '-p' after a '-a' or after a '-r'? From what you wrote below, that is after you do a '-a /usr/bin/tar', as it is being purged as well. Masami? > [root@s35lp76 perf]# ./perf buildid-cache -vp /usr/bin/ > Removing bash /usr/bin/: Ok > Removing dbus-daemon /usr/bin/: Ok > Removing ls /usr/bin/: Ok > Removing readlink /usr/bin/: Ok > Removing sleep /usr/bin/: Ok > Removing tar /usr/bin/: Ok > Removing time /usr/bin/: Ok > Removing vim /usr/bin/: Ok > Purging /usr/bin/: Ok In my test it works as advertised: [root@jouet ~]# perf buildid-cache -a /usr/bin/tar [root@jouet ~]# ls -la ~/.debug/.build-id/4c/10f253c0cb8459dd846235c0bc18929e4758ea lrwxrwxrwx. 1 root root 58 Oct 16 10:56 /root/.debug/.build-id/4c/10f253c0cb8459dd846235c0bc18929e4758ea -> ../../usr/bin/tar/4c10f253c0cb8459dd846235c0bc18929e4758ea [root@jouet ~]# ls -la ~/.debug/usr/bin/tar/4c10f253c0cb8459dd846235c0bc18929e4758ea total 424 drwxr-xr-x. 2 root root 4096 Oct 16 10:56 . drwxr-xr-x. 3 root root 4096 Oct 16 10:56 .. -rwxr-xr-x. 2 root root 425032 Jul 19 05:55 elf -rw-r--r--. 1 root root 0 Oct 16 10:56 probes [root@jouet ~]# perf buildid-cache -vp /usr/bin/tar Removing 4c10f253c0cb8459dd846235c0bc18929e4758ea /usr/bin/tar: Ok Purging /usr/bin/tar: Ok [root@jouet ~]# ls -la ~/.debug/usr/bin/tar/4c10f253c0cb8459dd846235c0bc18929e4758ea ls: cannot access '/root/.debug/usr/bin/tar/4c10f253c0cb8459dd846235c0bc18929e4758ea': No such file or directory [root@jouet ~]# ls -la ~/.debug/.build-id/4c/10f253c0cb8459dd846235c0bc18929e4758ea ls: cannot access '/root/.debug/.build-id/4c/10f253c0cb8459dd846235c0bc18929e4758ea': No such file or directory [root@jouet ~]# It was purged. Now lets try what you did, which is to ask for a path that will match with multiple binaries: [root@jouet ~]# perf buildid-cache -v -a /usr/bin/tar Adding 4c10f253c0cb8459dd846235c0bc18929e4758ea /usr/bin/tar: Ok [root@jouet ~]# ls -la ~/.debug/.build-id/4c/10f253c0cb8459dd846235c0bc18929e4758ea lrwxrwxrwx. 1 root root 58 Oct 16 10:58 /root/.debug/.build-id/4c/10f253c0cb8459dd846235c0bc18929e4758ea -> ../../usr/bin/tar/4c10f253c0cb8459dd846235c0bc18929e4758ea [root@jouet ~]# ls -la ~/.debug/usr/bin/tar/4c10f253c0cb8459dd846235c0bc18929e4758ea total 424 drwxr-xr-x. 2 root root 4096 Oct 16 10:58 . drwxr-xr-x. 3 root root 4096 Oct 16 10:58 .. -rwxr-xr-x. 2 root root 425032 Jul 19 05:55 elf -rw-r--r--. 1 root root 0 Oct 16 10:58 probes [root@jouet ~]# perf buildid-cache -vp /usr/bin Removing as /usr/bin: FAIL Purging /usr/bin: FAIL /usr/bin wasn't in the cache [root@jouet ~]# perf buildid-cache -vp /usr/bin/ Removing as /usr/bin/: FAIL Purging /usr/bin/: FAIL /usr/bin/ wasn't in the cache [root@jouet ~]# This is when --purge was added: commit 8d8c8e4cb3014fcc51f0e127b4316043306f5bb0 Author: Masami Hiramatsu Date: Fri Feb 27 13:50:26 2015 +0900 perf buildid-cache: Add --purge FILE to remove all caches of FILE ----------------------- > I have done some more debugging and there is something wrong. > The function > build_id_cache__purge_path() is called and > build_id_cache__list_build_ids() creates a list of file names located in /usr/bin of the buildid-cache. > build_id_cache__remove_s() is called for each name in the list and tries to locate each file name > in directory .buildid/YY/ZZZ..ZZZ which fails because > build_id_cache__linkname() expects a buildid and gets a file name. > The file name bash is treated as .buildid/ba/sh which does not exist. probably this got broken when the /elf, /probe separation was added, humm, unsure if a 'git bisect' would help here... Masami? > This seems to be a simple mistake so I wonder if I do something wrong. - Arnaldo