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perf probe: Accept %sdt and %cached event name 

To improve usability, support %[PROVIDER:]SDTEVENT format to add new
probes on SDT and cached events.

e.g.
  ----
  # perf probe -x /lib/libc-2.17.so  %lll_lock_wait_private
  Added new event:
    sdt_libc:lll_lock_wait_private (on %lll_lock_wait_private in /usr/lib/libc-2.17.so)

  You can now use it in all perf tools, such as:

          perf record -e sdt_libc:lll_lock_wait_private -aR sleep 1

  # perf probe -l | more
    sdt_libc:lll_lock_wait_private (on __lll_lock_wait_private+21 in /usr/lib/libc-2.17.so)
  ----

Note that this is not only for SDT events, but also normal
events with event-name.

e.g. define "myevent" on cache (-n doesn't add the real probe)
  ----
  # perf probe -x ./perf --cache -n --add 'myevent=dso__load $params'
  ----
  Reuse the "myevent" from cache as below.
  ----
  # perf probe -x ./perf %myevent
  ----

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/146831788372.17065.3645054540325909346.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Masami Hiramatsu 2016-07-12 19:04:43 +09:00 committed by Arnaldo Carvalho de Melo
parent f6eb0518f3
commit 36a009fe07
4 changed files with 76 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
tools/perf/Documentation/perf-probe.txt
View File

@ -151,6 +151,8 @@ Probe points are defined by following syntax.
3) Define event based on source file with lazy pattern
[[GROUP:]EVENT=]SRC;PTN [ARG ...]
4) Pre-defined SDT events or cached event with name
%[PROVIDER:]SDTEVENT
'EVENT' specifies the name of new event, if omitted, it will be set the name of the probed function. You can also specify a group name by 'GROUP', if omitted, set 'probe' is used for kprobe and 'probe_<bin>' is used for uprobe.
Note that using existing group name can conflict with other events. Especially, using the group name reserved for kernel modules can hide embedded events in the
@ -158,6 +160,11 @@ modules.
'FUNC' specifies a probed function name, and it may have one of the following options; '+OFFS' is the offset from function entry address in bytes, ':RLN' is the relative-line number from function entry line, and '%return' means that it probes function return. And ';PTN' means lazy matching pattern (see LAZY MATCHING). Note that ';PTN' must be the end of the probe point definition. In addition, '@SRC' specifies a source file which has that function.
It is also possible to specify a probe point by the source line number or lazy matching by using 'SRC:ALN' or 'SRC;PTN' syntax, where 'SRC' is the source file path, ':ALN' is the line number and ';PTN' is the lazy matching pattern.
'ARG' specifies the arguments of this probe point, (see PROBE ARGUMENT).
'SDTEVENT' and 'PROVIDER' is the pre-defined event name which is defined by user SDT (Statically Defined Tracing) or the pre-cached probes with event name.
Note that before using the SDT event, the target binary (on which SDT events are defined) must be scanned by linkperf:perf-buildid-cache[1] to make SDT events as cached events.
For details of the SDT, see below.
https://sourceware.org/gdb/onlinedocs/gdb/Static-Probe-Points.html
PROBE ARGUMENT
--------------
@ -237,4 +244,4 @@ Add probes at malloc() function on libc
SEE ALSO
--------
linkperf:perf-trace[1], linkperf:perf-record[1]
linkperf:perf-trace[1], linkperf:perf-record[1], linkperf:perf-buildid-cache[1]

82
tools/perf/util/probe-event.c
View File

@ -1197,6 +1197,34 @@ err:
return err;
}
static int parse_perf_probe_event_name(char **arg, struct perf_probe_event *pev)
{
char *ptr;
ptr = strchr(*arg, ':');
if (ptr) {
*ptr = '\0';
if (!is_c_func_name(*arg))
goto ng_name;
pev->group = strdup(*arg);
if (!pev->group)
return -ENOMEM;
*arg = ptr + 1;
} else
pev->group = NULL;
if (!is_c_func_name(*arg)) {
ng_name:
semantic_error("%s is bad for event name -it must "
"follow C symbol-naming rule.\n", *arg);
return -EINVAL;
}
pev->event = strdup(*arg);
if (pev->event == NULL)
return -ENOMEM;
return 0;
}
/* Parse probepoint definition. */
static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
{
@ -1204,38 +1232,43 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
char *ptr, *tmp;
char c, nc = 0;
bool file_spec = false;
int ret;
/*
* <Syntax>
* perf probe [GRP:][EVENT=]SRC[:LN|;PTN]
* perf probe [GRP:][EVENT=]FUNC[@SRC][+OFFS|%return|:LN|;PAT]
* perf probe %[GRP:]SDT_EVENT
*/
if (!arg)
return -EINVAL;
if (arg[0] == '%') {
pev->sdt = true;
arg++;
}
ptr = strpbrk(arg, ";=@+%");
if (pev->sdt) {
if (ptr) {
semantic_error("%s must contain only an SDT event name.\n", arg);
return -EINVAL;
}
ret = parse_perf_probe_event_name(&arg, pev);
if (ret == 0) {
if (asprintf(&pev->point.function, "%%%s", pev->event) < 0)
ret = -errno;
}
return ret;
}
if (ptr && *ptr == '=') { /* Event name */
*ptr = '\0';
tmp = ptr + 1;
ptr = strchr(arg, ':');
if (ptr) {
*ptr = '\0';
if (!is_c_func_name(arg))
goto not_fname;
pev->group = strdup(arg);
if (!pev->group)
return -ENOMEM;
arg = ptr + 1;
} else
pev->group = NULL;
if (!is_c_func_name(arg)) {
not_fname:
semantic_error("%s is bad for event name -it must "
"follow C symbol-naming rule.\n", arg);
return -EINVAL;
}
pev->event = strdup(arg);
if (pev->event == NULL)
return -ENOMEM;
ret = parse_perf_probe_event_name(&arg, pev);
if (ret < 0)
return ret;
arg = tmp;
}
@ -2876,7 +2909,8 @@ static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
entry = probe_cache__find(cache, pev);
if (!entry) {
ret = 0;
/* SDT must be in the cache */
ret = pev->sdt ? -ENOENT : 0;
goto out;
}
@ -2915,7 +2949,7 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev,
{
int ret;
if (!pev->group) {
if (!pev->group && !pev->sdt) {
/* Set group name if not given */
if (!pev->uprobes) {
pev->group = strdup(PERFPROBE_GROUP);
@ -2934,8 +2968,8 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev,
/* At first, we need to lookup cache entry */
ret = find_probe_trace_events_from_cache(pev, tevs);
if (ret > 0)
return ret; /* Found in probe cache */
if (ret > 0 || pev->sdt) /* SDT can be found only in the cache */
return ret == 0 ? -ENOENT : ret; /* Found in probe cache */
if (arch__prefers_symtab() && !perf_probe_event_need_dwarf(pev)) {
ret = find_probe_trace_events_from_map(pev, tevs);

1
tools/perf/util/probe-event.h
View File

@ -85,6 +85,7 @@ struct perf_probe_event {
char *group; /* Group name */
struct perf_probe_point point; /* Probe point */
int nargs; /* Number of arguments */
bool sdt; /* SDT/cached event flag */
bool uprobes; /* Uprobe event flag */
char *target; /* Target binary */
struct perf_probe_arg *args; /* Arguments */

9
tools/perf/util/probe-file.c
View File

@ -547,6 +547,15 @@ probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
return NULL;
list_for_each_entry(entry, &pcache->entries, node) {
if (pev->sdt) {
if (entry->pev.event &&
streql(entry->pev.event, pev->event) &&
(!pev->group ||
streql(entry->pev.group, pev->group)))
goto found;
continue;
}
/* Hit if same event name or same command-string */
if ((pev->event &&
(streql(entry->pev.group, pev->group) &&