* [PATCH] tools/perf: Disable perf probe when libtraceevent is missing @ 2023-01-20 12:02 Athira Rajeev 2023-01-20 14:28 ` Arnaldo Carvalho de Melo 0 siblings, 1 reply; 3+ messages in thread From: Athira Rajeev @ 2023-01-20 12:02 UTC (permalink / raw) To: acme, jolsa, irogers Cc: ak, namhyung, james.clark, mpe, linux-perf-users, linuxppc-dev, maddy, rnsastry, kjain, disgoel While parsing the tracepoint events in parse_events_add_tracepoint() function, code checks for HAVE_LIBTRACEEVENT support. This is needed since libtraceevent is necessary for tracepoint. But while adding probe points, check for LIBTRACEEVENT is not done in case of perf probe. Hence, in environment with missing libtraceevent-devel, it is observed that adding a probe point works even though its not supported. Example: Adding probe point: ./perf probe 'vfs_getname=getname_flags:72 pathname=result->name:string' Added new event: probe:vfs_getname (on getname_flags:72 with pathname=result->name:string) You can now use it in all perf tools, such as: perf record -e probe:vfs_getname -aR sleep 1 But trying perf record: ./perf record -e probe:vfs_getname -aR sleep 1 event syntax error: 'probe:vfs_getname' \___ unsupported tracepoint libtraceevent is necessary for tracepoint support Run 'perf list' for a list of valid events Fix this by wrapping "builtin-probe" compilation and "perf probe" usage under "CONFIG_LIBTRACEEVENT" check. Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> --- tools/perf/Build | 4 +++- tools/perf/perf.c | 2 ++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/perf/Build b/tools/perf/Build index 6dd67e502295..a138a2304929 100644 --- a/tools/perf/Build +++ b/tools/perf/Build @@ -33,7 +33,9 @@ ifeq ($(CONFIG_LIBTRACEEVENT),y) perf-$(CONFIG_TRACE) += trace/beauty/ endif -perf-$(CONFIG_LIBELF) += builtin-probe.o +ifeq ($(CONFIG_LIBTRACEEVENT),y) + perf-$(CONFIG_LIBELF) += builtin-probe.o +endif perf-y += bench/ perf-y += tests/ diff --git a/tools/perf/perf.c b/tools/perf/perf.c index 82bbe0ca858b..7b0d79284d5a 100644 --- a/tools/perf/perf.c +++ b/tools/perf/perf.c @@ -80,9 +80,11 @@ static struct cmd_struct commands[] = { #ifdef HAVE_LIBTRACEEVENT { "sched", cmd_sched, 0 }, #endif +#ifdef HAVE_LIBTRACEEVENT #ifdef HAVE_LIBELF_SUPPORT { "probe", cmd_probe, 0 }, #endif +#endif #ifdef HAVE_LIBTRACEEVENT { "kmem", cmd_kmem, 0 }, { "lock", cmd_lock, 0 }, -- 2.39.0 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] tools/perf: Disable perf probe when libtraceevent is missing 2023-01-20 12:02 [PATCH] tools/perf: Disable perf probe when libtraceevent is missing Athira Rajeev @ 2023-01-20 14:28 ` Arnaldo Carvalho de Melo 2023-01-25 14:46 ` Athira Rajeev 0 siblings, 1 reply; 3+ messages in thread From: Arnaldo Carvalho de Melo @ 2023-01-20 14:28 UTC (permalink / raw) To: Athira Rajeev Cc: jolsa, irogers, ak, namhyung, james.clark, mpe, linux-perf-users, linuxppc-dev, maddy, rnsastry, kjain, disgoel Em Fri, Jan 20, 2023 at 05:32:56PM +0530, Athira Rajeev escreveu: > While parsing the tracepoint events in parse_events_add_tracepoint() > function, code checks for HAVE_LIBTRACEEVENT support. This is needed > since libtraceevent is necessary for tracepoint. But while adding > probe points, check for LIBTRACEEVENT is not done in case of perf probe. > Hence, in environment with missing libtraceevent-devel, it is > observed that adding a probe point works even though its not > supported. > Example: > Adding probe point: > ./perf probe 'vfs_getname=getname_flags:72 pathname=result->name:string' > Added new event: > probe:vfs_getname (on getname_flags:72 with pathname=result->name:string) > You can now use it in all perf tools, such as: > perf record -e probe:vfs_getname -aR sleep 1 > But trying perf record: > ./perf record -e probe:vfs_getname -aR sleep 1 > event syntax error: 'probe:vfs_getname' > \___ unsupported tracepoint > libtraceevent is necessary for tracepoint support > Run 'perf list' for a list of valid events > > Fix this by wrapping "builtin-probe" compilation and > "perf probe" usage under "CONFIG_LIBTRACEEVENT" check. Humm, but 'perf probe' continues to work, as uou demoed above, the problem is with the suggestion to use other perf tools that need to parse tracefs and without libtraceevent, currently can't do it: [root@quaco ~]# perf probe 'vfs_getname=getname_flags:72 pathname=result->name:string' Added new event: probe:vfs_getname (on getname_flags:72 with pathname=result->name:string) You can now use it in all perf tools, such as: perf record -e probe:vfs_getname -aR sleep 1 [root@quaco ~]# perf probe -l probe:vfs_getname (on getname_flags:72@fs/namei.c with pathname) [root@quaco ~]# perf trace -e probe:vfs_getname perf: 'trace' is not a perf-command. See 'perf --help'. [root@quaco ~]# cd /sys/kernel/tracing/events/probe/vfs_getname/ [root@quaco vfs_getname]# ls enable filter format hist id trigger [root@quaco vfs_getname]# ls -la total 0 drwxr-x---. 2 root root 0 Jan 20 11:18 . drwxr-x---. 3 root root 0 Jan 20 11:18 .. -rw-r-----. 1 root root 0 Jan 20 11:18 enable -rw-r-----. 1 root root 0 Jan 20 11:18 filter -r--r-----. 1 root root 0 Jan 20 11:18 format -r--r-----. 1 root root 0 Jan 20 11:18 hist -r--r-----. 1 root root 0 Jan 20 11:18 id -rw-r-----. 1 root root 0 Jan 20 11:18 trigger [root@quaco vfs_getname]# But we can go on from there: [root@quaco tracing]# pwd /sys/kernel/tracing [root@quaco tracing]# echo 1 > /sys/kernel/tracing/events/probe/vfs_getname/enable [root@quaco tracing]# echo 1 > tracing_on [root@quaco tracing]# head trace_pipe systemd-oomd-979 [003] ..... 96369.978971: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service" systemd-oomd-979 [003] ..... 96369.979022: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/memory.current" systemd-oomd-979 [003] ..... 96369.979084: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="" systemd-oomd-979 [003] ..... 96369.979162: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/memory.min" systemd-oomd-979 [003] ..... 96369.979197: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="" systemd-oomd-979 [003] ..... 96369.979267: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/memory.low" systemd-oomd-979 [003] ..... 96369.979303: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="" systemd-oomd-979 [003] ..... 96369.979372: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/memory.swap.current" systemd-oomd-979 [003] ..... 96369.979406: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="" systemd-oomd-979 [003] ..... 96369.979475: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/memory.stat" [root@quaco tracing]# So you could instead replace the suggestion from: " You can now use it in all perf tools, such as: perf record -e probe:vfs_getname -aR sleep 1 " To: " perf is not linked with libtraceevent, to use the new probe you can use tracefs: cd /sys/kernel/tracing/ echo 1 > events/probe/vfs_getname/enable echo 1 > tracing_on cat trace_pipe " wdyt? - Arnaldo > Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> > --- > tools/perf/Build | 4 +++- > tools/perf/perf.c | 2 ++ > 2 files changed, 5 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/Build b/tools/perf/Build > index 6dd67e502295..a138a2304929 100644 > --- a/tools/perf/Build > +++ b/tools/perf/Build > @@ -33,7 +33,9 @@ ifeq ($(CONFIG_LIBTRACEEVENT),y) > perf-$(CONFIG_TRACE) += trace/beauty/ > endif > > -perf-$(CONFIG_LIBELF) += builtin-probe.o > +ifeq ($(CONFIG_LIBTRACEEVENT),y) > + perf-$(CONFIG_LIBELF) += builtin-probe.o > +endif > > perf-y += bench/ > perf-y += tests/ > diff --git a/tools/perf/perf.c b/tools/perf/perf.c > index 82bbe0ca858b..7b0d79284d5a 100644 > --- a/tools/perf/perf.c > +++ b/tools/perf/perf.c > @@ -80,9 +80,11 @@ static struct cmd_struct commands[] = { > #ifdef HAVE_LIBTRACEEVENT > { "sched", cmd_sched, 0 }, > #endif > +#ifdef HAVE_LIBTRACEEVENT > #ifdef HAVE_LIBELF_SUPPORT > { "probe", cmd_probe, 0 }, > #endif > +#endif > #ifdef HAVE_LIBTRACEEVENT > { "kmem", cmd_kmem, 0 }, > { "lock", cmd_lock, 0 }, > -- > 2.39.0 -- - Arnaldo ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] tools/perf: Disable perf probe when libtraceevent is missing 2023-01-20 14:28 ` Arnaldo Carvalho de Melo @ 2023-01-25 14:46 ` Athira Rajeev 0 siblings, 0 replies; 3+ messages in thread From: Athira Rajeev @ 2023-01-25 14:46 UTC (permalink / raw) To: Arnaldo Carvalho de Melo Cc: Ian Rogers, Andi Kleen, Nageswara Sastry, linux-perf-users, Madhavan Srinivasan, James Clark, Jiri Olsa, Kajol Jain, Namhyung Kim, disgoel, linuxppc-dev > On 20-Jan-2023, at 7:58 PM, Arnaldo Carvalho de Melo <acme@kernel.org> wrote: > > Em Fri, Jan 20, 2023 at 05:32:56PM +0530, Athira Rajeev escreveu: >> While parsing the tracepoint events in parse_events_add_tracepoint() >> function, code checks for HAVE_LIBTRACEEVENT support. This is needed >> since libtraceevent is necessary for tracepoint. But while adding >> probe points, check for LIBTRACEEVENT is not done in case of perf probe. >> Hence, in environment with missing libtraceevent-devel, it is >> observed that adding a probe point works even though its not >> supported. > >> Example: >> Adding probe point: >> ./perf probe 'vfs_getname=getname_flags:72 pathname=result->name:string' >> Added new event: >> probe:vfs_getname (on getname_flags:72 with pathname=result->name:string) > >> You can now use it in all perf tools, such as: > >> perf record -e probe:vfs_getname -aR sleep 1 > >> But trying perf record: >> ./perf record -e probe:vfs_getname -aR sleep 1 >> event syntax error: 'probe:vfs_getname' >> \___ unsupported tracepoint >> libtraceevent is necessary for tracepoint support >> Run 'perf list' for a list of valid events >> >> Fix this by wrapping "builtin-probe" compilation and >> "perf probe" usage under "CONFIG_LIBTRACEEVENT" check. > > Humm, but 'perf probe' continues to work, as uou demoed above, the > problem is with the suggestion to use other perf tools that need to > parse tracefs and without libtraceevent, currently can't do it: > > [root@quaco ~]# perf probe 'vfs_getname=getname_flags:72 pathname=result->name:string' > Added new event: > probe:vfs_getname (on getname_flags:72 with pathname=result->name:string) > > You can now use it in all perf tools, such as: > > perf record -e probe:vfs_getname -aR sleep 1 > > [root@quaco ~]# perf probe -l > probe:vfs_getname (on getname_flags:72@fs/namei.c with pathname) > [root@quaco ~]# perf trace -e probe:vfs_getname > perf: 'trace' is not a perf-command. See 'perf --help'. > [root@quaco ~]# cd /sys/kernel/tracing/events/probe/vfs_getname/ > [root@quaco vfs_getname]# ls > enable filter format hist id trigger > [root@quaco vfs_getname]# ls -la > total 0 > drwxr-x---. 2 root root 0 Jan 20 11:18 . > drwxr-x---. 3 root root 0 Jan 20 11:18 .. > -rw-r-----. 1 root root 0 Jan 20 11:18 enable > -rw-r-----. 1 root root 0 Jan 20 11:18 filter > -r--r-----. 1 root root 0 Jan 20 11:18 format > -r--r-----. 1 root root 0 Jan 20 11:18 hist > -r--r-----. 1 root root 0 Jan 20 11:18 id > -rw-r-----. 1 root root 0 Jan 20 11:18 trigger > [root@quaco vfs_getname]# > > But we can go on from there: > > [root@quaco tracing]# pwd > /sys/kernel/tracing > [root@quaco tracing]# echo 1 > /sys/kernel/tracing/events/probe/vfs_getname/enable > [root@quaco tracing]# echo 1 > tracing_on > [root@quaco tracing]# head trace_pipe > systemd-oomd-979 [003] ..... 96369.978971: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service" > systemd-oomd-979 [003] ..... 96369.979022: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/memory.current" > systemd-oomd-979 [003] ..... 96369.979084: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="" > systemd-oomd-979 [003] ..... 96369.979162: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/memory.min" > systemd-oomd-979 [003] ..... 96369.979197: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="" > systemd-oomd-979 [003] ..... 96369.979267: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/memory.low" > systemd-oomd-979 [003] ..... 96369.979303: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="" > systemd-oomd-979 [003] ..... 96369.979372: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/memory.swap.current" > systemd-oomd-979 [003] ..... 96369.979406: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="" > systemd-oomd-979 [003] ..... 96369.979475: vfs_getname: (getname_flags.part.0+0x6b/0x1c0) pathname="/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/memory.stat" > [root@quaco tracing]# > > So you could instead replace the suggestion from: > > " > You can now use it in all perf tools, such as: > > perf record -e probe:vfs_getname -aR sleep 1 > " > > To: > > " > perf is not linked with libtraceevent, to use the new probe you > can use tracefs: > > cd /sys/kernel/tracing/ > echo 1 > events/probe/vfs_getname/enable > echo 1 > tracing_on > cat trace_pipe > " > > wdyt? Hi Arnaldo, Thanks for the suggestion. The idea to change usage message based on presence of libtraceevent is good. I could try change with HAVE_LIBTRACEEVENT condition. Sample snippet below: diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c index ed73d0b89ca2..f010d0e43577 100644 --- a/tools/perf/builtin-probe.c +++ b/tools/perf/builtin-probe.c @@ -383,9 +383,17 @@ static int perf_add_probe_events(struct perf_probe_event *pevs, int npevs) /* Note that it is possible to skip all events because of blacklist */ if (event) { +#ifndef HAVE_LIBTRACEEVENT + pr_info("\nperf is not linked with libtraceevent, to use the new probe you can use tracefs:\n\n"); + pr_info("\tcd /sys/kernel/tracing/\n"); + pr_info("\techo 1 > events/%s/%s/enable\n", group, event); + pr_info("\techo 1 > tracing_on\n"); + pr_info("\tcat trace_pipe\n"); +#else /* Show how to use the event. */ pr_info("\nYou can now use it in all perf tools, such as:\n\n"); pr_info("\tperf record -e %s:%s -aR sleep 1\n\n", group, event); +#endif } out_cleanup: I will re-work on patch changes and also test for other options ( perf probe with different group “GROUP" values etc) to make sure this works via tracefs. Arnaldo, the above approach looks fine to proceed with ? Thanks Athira > > - Arnaldo > >> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> >> --- >> tools/perf/Build | 4 +++- >> tools/perf/perf.c | 2 ++ >> 2 files changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/tools/perf/Build b/tools/perf/Build >> index 6dd67e502295..a138a2304929 100644 >> --- a/tools/perf/Build >> +++ b/tools/perf/Build >> @@ -33,7 +33,9 @@ ifeq ($(CONFIG_LIBTRACEEVENT),y) >> perf-$(CONFIG_TRACE) += trace/beauty/ >> endif >> >> -perf-$(CONFIG_LIBELF) += builtin-probe.o >> +ifeq ($(CONFIG_LIBTRACEEVENT),y) >> + perf-$(CONFIG_LIBELF) += builtin-probe.o >> +endif >> >> perf-y += bench/ >> perf-y += tests/ >> diff --git a/tools/perf/perf.c b/tools/perf/perf.c >> index 82bbe0ca858b..7b0d79284d5a 100644 >> --- a/tools/perf/perf.c >> +++ b/tools/perf/perf.c >> @@ -80,9 +80,11 @@ static struct cmd_struct commands[] = { >> #ifdef HAVE_LIBTRACEEVENT >> { "sched", cmd_sched, 0 }, >> #endif >> +#ifdef HAVE_LIBTRACEEVENT >> #ifdef HAVE_LIBELF_SUPPORT >> { "probe", cmd_probe, 0 }, >> #endif >> +#endif >> #ifdef HAVE_LIBTRACEEVENT >> { "kmem", cmd_kmem, 0 }, >> { "lock", cmd_lock, 0 }, >> -- >> 2.39.0 > > -- > > - Arnaldo ^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-01-25 14:47 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2023-01-20 12:02 [PATCH] tools/perf: Disable perf probe when libtraceevent is missing Athira Rajeev 2023-01-20 14:28 ` Arnaldo Carvalho de Melo 2023-01-25 14:46 ` Athira Rajeev
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