On Fri, 3 Feb 2017 15:56:42 +0530 Ravi Bangoria <[email protected]> wrote:
> All events from 'perf list', except SDT events, can be directly recorded > with 'perf record'. But, the flow is little different for SDT events. > Probe point for SDT event needs to be created using 'perf probe' before > recording it using 'perf record'. Perf shows misleading hint when user > tries to record SDT event without creating a probe point. Show proper > hint there. > > Before patch: > $ perf record -a -e sdt_glib:idle__add > event syntax error: 'sdt_glib:idle__add' > \___ unknown tracepoint > > Error: File /sys/kernel/debug/tracing/events/sdt_glib/idle__add not found. > Hint: Perhaps this kernel misses some CONFIG_ setting to enable this > feature?. > ... > > After patch: > $ perf record -a -e sdt_glib:idle__add > event syntax error: 'sdt_glib:idle__add' > \___ unknown tracepoint > > Error: File /sys/kernel/debug/tracing/events/sdt_glib/idle__add not found. > Hint: SDT event cannot be directly recorded on. Please use 'perf probe > sdt_glib:idle__add' before recording it. > ... > > $ perf probe sdt_glib:idle__add > Added new event: > sdt_glib:idle__add (on %idle__add in > /usr/lib64/libglib-2.0.so.0.5000.2) > > You can now use it in all perf tools, such as: > > perf record -e sdt_glib:idle__add -aR sleep 1 > > $ perf record -a -e sdt_glib:idle__add > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.175 MB perf.data ] > Looks good to me:) Acked-by: Masami Hiramatsu <[email protected]> Thanks! > Suggested-by: Ingo Molnar <[email protected]> > Signed-off-by: Ravi Bangoria <[email protected]> > --- > Changes in v2: > - More precise hint > > tools/lib/api/fs/tracing_path.c | 31 +++++++++++++++++-------------- > 1 file changed, 17 insertions(+), 14 deletions(-) > > diff --git a/tools/lib/api/fs/tracing_path.c b/tools/lib/api/fs/tracing_path.c > index 251b7c3..aaafc99 100644 > --- a/tools/lib/api/fs/tracing_path.c > +++ b/tools/lib/api/fs/tracing_path.c > @@ -86,9 +86,13 @@ void put_tracing_file(char *file) > free(file); > } > > -static int strerror_open(int err, char *buf, size_t size, const char > *filename) > +int tracing_path__strerror_open_tp(int err, char *buf, size_t size, > + const char *sys, const char *name) > { > char sbuf[128]; > + char filename[PATH_MAX]; > + > + snprintf(filename, PATH_MAX, "%s/%s", sys, name ?: "*"); > > switch (err) { > case ENOENT: > @@ -99,10 +103,18 @@ static int strerror_open(int err, char *buf, size_t > size, const char *filename) > * - jirka > */ > if (debugfs__configured() || tracefs__configured()) { > - snprintf(buf, size, > - "Error:\tFile %s/%s not found.\n" > - "Hint:\tPerhaps this kernel misses some > CONFIG_ setting to enable this feature?.\n", > - tracing_events_path, filename); > + /* sdt markers */ > + if (!strncmp(filename, "sdt_", 4)) { > + snprintf(buf, size, > + "Error:\tFile %s/%s not found.\n" > + "Hint:\tSDT event cannot be directly > recorded on. Please use 'perf probe %s:%s' before recording it.\n", > + tracing_events_path, filename, sys, > name); > + } else { > + snprintf(buf, size, > + "Error:\tFile %s/%s not found.\n" > + "Hint:\tPerhaps this kernel misses > some CONFIG_ setting to enable this feature?.\n", > + tracing_events_path, filename); > + } > break; > } > snprintf(buf, size, "%s", > @@ -125,12 +137,3 @@ static int strerror_open(int err, char *buf, size_t > size, const char *filename) > > return 0; > } > - > -int tracing_path__strerror_open_tp(int err, char *buf, size_t size, const > char *sys, const char *name) > -{ > - char path[PATH_MAX]; > - > - snprintf(path, PATH_MAX, "%s/%s", sys, name ?: "*"); > - > - return strerror_open(err, buf, size, path); > -} > -- > 2.9.3 > -- Masami Hiramatsu <[email protected]>
