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path: root/tools/lib/api/fs/tracing_path.c
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2017-02-08perf sdt: Show proper hint when event not yet in place via 'perf probe'Ravi Bangoria1-14/+18
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 points for SDT event needs to be created using 'perf probe' before recording it using 'perf record'. Perf shows misleading hint when a user tries to record SDT event without first 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 first 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 ] Suggested-and-Acked-by: Ingo Molnar <mingo@redhat.com> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexis Berlemont <alexis.berlemont@gmail.com> Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20170203102642.17258-1-ravi.bangoria@linux.vnet.ibm.com [ s/Please use/Please first use/ and break the Hint line in two ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-07-12tools lib api fs: Use str_error_r()Arnaldo Carvalho de Melo1-1/+2
To make it portable to non-glibc systems, that follow the XSI variant instead of the GNU specific one that gets in place when _GNU_SOURCE is defined. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/n/tip-mixgnh3iyajuqogn2opsocdy@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-10-05tools lib api fs: No need to use PATH_MAX + 1Jiri Olsa1-3/+3
Because there's no point, PATH_MAX is big enough. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1444068369-20978-2-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-09-28tools lib api fs: Store tracing mountpoint for better error messageJiri Olsa1-10/+3
Storing the actual tracing path mountpoint to display correct error message hint ('Hint:' line). The error hint rediscovers mountpoints, but it could be different from what we actually used in tracing path. Before we'd display debugfs mount even though tracefs was used: $ perf record -e sched:sched_krava ls event syntax error: 'sched:sched_krava' \___ can't access trace events Error: No permissions to read /sys/kernel/debug/tracing/events/sched/sched_krava Hint: Try 'sudo mount -o remount,mode=755 /sys/kernel/debug' ... After this change, correct mountpoint is displayed: $ perf record -e sched:sched_krava ls event syntax error: 'sched:sched_krava' \___ can't access trace events Error: No permissions to read /sys/kernel/debug/tracing/events/sched/sched_krava Hint: Try 'sudo mount -o remount,mode=755 /sys/kernel/debug/tracing' ... Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: David Ahern <dsahern@gmail.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Raphael Beamonte <raphael.beamonte@gmail.com> Link: http://lkml.kernel.org/r/1442674027-19427-1-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-09-14tools lib api fs: Replace debugfs/tracefs objects interface with fs.cJiri Olsa1-8/+7
Switching to the fs.c related filesystem framework. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: David Ahern <dsahern@gmail.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Raphael Beamonte <raphael.beamonte@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1441180605-24737-14-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-09-14tools lib api fs: Make tracing_path_strerror_open message genericJiri Olsa1-10/+16
Making tracing_path__strerror_open_tp message generic by mentioning both debugfs/tracefs words in error message plus the tracing_path instead of debugfs_mountpoint. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: David Ahern <dsahern@gmail.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Raphael Beamonte <raphael.beamonte@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1441180605-24737-7-git-send-email-jolsa@kernel.org [ Add comment for the ENOENT case out of this patch discussion thread ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-09-04tools lib api fs: Move debugfs__strerror_open into tracing_path.c objectJiri Olsa1-0/+54
Moving debugfs__strerror_open out of api/fs/debugfs.c, because it's not debugfs specific. It'll be changed to consider tracefs mount as well in following patches. Renaming it into tracing_path__strerror_open_tp to fit into the namespace. No functional change is intended. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Reviewed-by: Matt Fleming <matt.fleming@intel.com> Cc: Raphael Beamonte <raphael.beamonte@gmail.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1441180605-24737-6-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-09-04tools lib api fs: Move tracing_path interface into api/fs/tracing_path.cJiri Olsa1-0/+83
Moving tracing_path interface into api/fs/tracing_path.c out of util.c. It seems generic enough to be used by others, and I couldn't think of better place. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Reviewed-by: Matt Fleming <matt.fleming@intel.com> Reviewed-by: Raphael Beamonte <raphael.beamonte@gmail.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1441180605-24737-5-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>