From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751545AbcGNAHd (ORCPT ); Wed, 13 Jul 2016 20:07:33 -0400 Received: from mail.kernel.org ([198.145.29.136]:37514 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751342AbcGNAHZ (ORCPT ); Wed, 13 Jul 2016 20:07:25 -0400 Date: Wed, 13 Jul 2016 21:07:19 -0300 From: Arnaldo Carvalho de Melo To: Masami Hiramatsu Cc: linux-kernel@vger.kernel.org, Namhyung Kim , Peter Zijlstra , Ingo Molnar , Hemant Kumar , Ananth N Mavinakayanahalli , Brendan Gregg Subject: Re: [PATCH perf/core 07/10] perf probe: Support @BUILDID or @FILE suffix for SDT events Message-ID: <20160714000719.GC6961@kernel.org> References: <146831786245.17065.7237942149862581005.stgit@devbox> <146831793746.17065.13065062753978236612.stgit@devbox> <20160713195019.GA2927@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160713195019.GA2927@kernel.org> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Wed, Jul 13, 2016 at 04:50:19PM -0300, Arnaldo Carvalho de Melo escreveu: > Em Tue, Jul 12, 2016 at 07:05:37PM +0900, Masami Hiramatsu escreveu: > > Support @BUILDID or @FILE suffix for SDT events. This allows > > perf to add probes on SDTs/pre-cached events on given FILE > > or the file which has given BUILDID (also, this complements > > BUILDID.) > > For example, both gcc and libstdc++ has same SDTs as below. > > If you would like to add a probe on sdt_libstdcxx:catch on gcc, > > you can do as below. > > Ok, how to add those entries? > > [root@jouet hello_world]# perf probe -x /usr/bin/gcc -a %sdt_gcc:\* > Error: Failed to add events. > [root@jouet hello_world]# perf probe --verbose -x /usr/bin/gcc -a %sdt_gcc:\* > probe-definition(0): %sdt_gcc:* > 0 arguments > symbol:throw file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:rethrow file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:catch file:(null) line:0 offset:0 return:0 lazy:(null) > symbol:unwind file:(null) line:0 offset:0 return:0 lazy:(null) > Error: Failed to add events. Reason: No such file or directory (Code: -2) > [root@jouet hello_world]# So, ok, I managed with: [root@jouet ~]# perf probe -x /usr/bin/gcc %sdt_libstdcxx:\* Added new events: sdt_libstdcxx:throw (on %* in /usr/bin/gcc) sdt_libstdcxx:rethrow (on %* in /usr/bin/gcc) sdt_libstdcxx:catch (on %* in /usr/bin/gcc) You can now use it in all perf tools, such as: perf record -e sdt_libstdcxx:catch -aR sleep 1 [root@jouet ~]# I then tried to remove the events just created: # perf probe -d %sdt_libstdcxx:\* # It tells me nothing, cool, probably it removed it all, then I go and try re-adding them: [root@jouet ~]# perf probe -x /usr/bin/gcc %sdt_libstdcxx:\* Error: event "throw" already exists. Hint: Remove existing event by 'perf probe -d' or force duplicates by 'perf probe -f' or set 'force=yes' in BPF source. Error: Failed to add events. [root@jouet ~]# Huh? Then I tried like you did above, using 'perf list sdt' [root@jouet ~]# perf list sdt List of pre-defined events (to be used in -e): [root@jouet ~]# But they appear via 'perf probe -l' [root@jouet ~]# perf probe -l sdt_libs* sdt_libstdcxx:catch (on execute_cfa_program+1551@../../../libgcc/unwind-dw2.c in /usr/bin/gcc) sdt_libstdcxx:rethrow (on d_print_subexpr+280@libsupc++/cp-demangle.c in /usr/bin/gcc) sdt_libstdcxx:throw (on d_print_subexpr+93@libsupc++/cp-demangle.c in /usr/bin/gcc) [root@jouet ~]# There is no event, then, guessing, I tried removing that %, since I don't see it in the 'perf probe -l' output, so it must've been just some distracting artifact at the time of adding the SDT prove: [root@jouet ~]# perf probe -d sdt_libstdcxx:\* Removed event: sdt_libstdcxx:catch Removed event: sdt_libstdcxx:rethrow Removed event: sdt_libstdcxx:throw [root@jouet ~]# perf probe -l sdt_libs* [root@jouet ~]# Ok, now it works, but then if I try having both the gcc and libstdc++ ones, I can't: [root@jouet ~]# perf probe -x /usr/lib64/libstdc++.so.6 %sdt_libstdcxx:\* Error: event "catch" already exists. Hint: Remove existing event by 'perf probe -d' or force duplicates by 'perf probe -f' or set 'force=yes' in BPF source. Error: Failed to add events. So I forced it: [root@jouet ~]# perf probe -f -x /usr/lib64/libstdc++.so.6 %sdt_libstdcxx:\* Added new events: sdt_libstdcxx:catch_1 (on %* in /usr/lib64/libstdc++.so.6.0.22) sdt_libstdcxx:throw_1 (on %* in /usr/lib64/libstdc++.so.6.0.22) sdt_libstdcxx:rethrow_1 (on %* in /usr/lib64/libstdc++.so.6.0.22) You can now use it in all perf tools, such as: perf record -e sdt_libstdcxx:rethrow_1 -aR sleep 1 [root@jouet ~]# If it will rename it, why require -f? Where is the duplicity? If I go and re-read all the discussion on the thread that lead to these patches, I may figure out all those questions, but then, that would be a lot of info to have in mind :-\ I.e. I would suggest that no -f should be needed, that that "Error: event "catch" already exists" shouldn't be even emitted, since those will be different events, i.e. one is named "sdt_libstdcxx:catch" and the other "sdt_libstdcxx:catch_1"... But that becomes an usability problem, couldn't it have the basename in it? I.e.: sdt_gcc_libstdcxx:catch and sdt_libstdc++:catch? I'm going to look my inbox for patches I overlook that added 'perf list sdt'... - Arnaldo > Can those messages be improved? What am I missing? > > > ---- > > # perf list sdt | tail -n 6 > > sdt_libstdcxx:catch@/usr/bin/gcc(0cc207fc4b27) [SDT event] > > sdt_libstdcxx:catch@/usr/lib64/libstdc++.so.6.0.20(91c7a88fdf49) > > sdt_libstdcxx:rethrow@/usr/bin/gcc(0cc207fc4b27) [SDT event] > > sdt_libstdcxx:rethrow@/usr/lib64/libstdc++.so.6.0.20(91c7a88fdf49) > > sdt_libstdcxx:throw@/usr/bin/gcc(0cc207fc4b27) [SDT event] > > sdt_libstdcxx:throw@/usr/lib64/libstdc++.so.6.0.20(91c7a88fdf49) > > # perf probe -a %sdt_libstdcxx:catch@0cc > > Added new event: > > sdt_libstdcxx:catch (on %catch in /usr/bin/gcc) > > > > You can now use it in all perf tools, such as: > > > > perf record -e sdt_libstdcxx:catch -aR sleep 1 > > ---- > > > > Signed-off-by: Masami Hiramatsu > > --- > > Changes in v12: > > - Rename strlist__for_each to strlist__for_each_entry. > > --- > > tools/perf/util/build-id.c | 43 +++++++++++++++++++++++++++++++++++++++++ > > tools/perf/util/build-id.h | 1 + > > tools/perf/util/probe-event.c | 17 ++++++++++++++-- > > 3 files changed, 59 insertions(+), 2 deletions(-) > > > > diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c > > index 8e86a83..e59003e 100644 > > --- a/tools/perf/util/build-id.c > > +++ b/tools/perf/util/build-id.c > > @@ -523,6 +523,49 @@ err_out: > > goto out_free; > > } > > > > +static bool str_is_build_id(const char *maybe_sbuild_id, size_t len) > > +{ > > + size_t i; > > + > > + for (i = 0; i < len; i++) { > > + if (!isxdigit(maybe_sbuild_id[i])) > > + return false; > > + } > > + return true; > > +} > > + > > +/* Return the valid complete build-id */ > > +char *build_id_cache__complement(const char *incomplete_sbuild_id) > > +{ > > + struct strlist *bidlist; > > + struct str_node *nd, *cand = NULL; > > + char *sbuild_id = NULL; > > + size_t len = strlen(incomplete_sbuild_id); > > + > > + if (len >= SBUILD_ID_SIZE || > > + !str_is_build_id(incomplete_sbuild_id, len)) > > + return NULL; > > + > > + bidlist = build_id_cache__list_all(true); > > + if (!bidlist) > > + return NULL; > > + > > + strlist__for_each_entry(nd, bidlist) { > > + if (strncmp(nd->s, incomplete_sbuild_id, len) != 0) > > + continue; > > + if (cand) { /* Error: There are more than 2 candidates. */ > > + cand = NULL; > > + break; > > + } > > + cand = nd; > > + } > > + if (cand) > > + sbuild_id = strdup(cand->s); > > + strlist__delete(bidlist); > > + > > + return sbuild_id; > > +} > > + > > char *build_id_cache__cachedir(const char *sbuild_id, const char *name, > > bool is_kallsyms, bool is_vdso) > > { > > diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h > > index 64e740f..d279906 100644 > > --- a/tools/perf/util/build-id.h > > +++ b/tools/perf/util/build-id.h > > @@ -35,6 +35,7 @@ char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size); > > char *build_id_cache__cachedir(const char *sbuild_id, const char *name, > > bool is_kallsyms, bool is_vdso); > > struct strlist *build_id_cache__list_all(bool validonly); > > +char *build_id_cache__complement(const char *incomplete_sbuild_id); > > int build_id_cache__list_build_ids(const char *pathname, > > struct strlist **result); > > bool build_id_cache__cached(const char *sbuild_id); > > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c > > index 679aa6b..0dadaa3 100644 > > --- a/tools/perf/util/probe-event.c > > +++ b/tools/perf/util/probe-event.c > > @@ -1251,8 +1251,21 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev) > > ptr = strpbrk(arg, ";=@+%"); > > if (pev->sdt) { > > if (ptr) { > > - semantic_error("%s must contain only an SDT event name.\n", arg); > > - return -EINVAL; > > + if (*ptr != '@') { > > + semantic_error("%s must be an SDT name.\n", > > + arg); > > + return -EINVAL; > > + } > > + /* This must be a target file name or build id */ > > + tmp = build_id_cache__complement(ptr + 1); > > + if (tmp) { > > + pev->target = build_id_cache__origname(tmp); > > + free(tmp); > > + } else > > + pev->target = strdup(ptr + 1); > > + if (!pev->target) > > + return -ENOMEM; > > + *ptr = '\0'; > > } > > ret = parse_perf_probe_event_name(&arg, pev); > > if (ret == 0) {