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Subject[PATCH -tip perf/probes 09/10] perf/probes: Change probepoint syntax of perf-probe
Date
This changes probe point syntax of perf-probe as below

<SRC>[:ABS_LN] [ARGS]
or
<FUNC>[+OFFS|%return][@SRC] [ARGS]

And event name and event group name are automatically
generated based on probe-symbol and offset as below.

perfprobes/SYMBOL_OFFSET[_NUM]

Where SYMBOL is the probing symbol and OFFSET is
the byte offset from the symbol.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---

tools/perf/builtin-probe.c | 181 +++++++++++++++++++++++++---------------
tools/perf/util/probe-finder.c | 10 ++
tools/perf/util/probe-finder.h | 2
3 files changed, 123 insertions(+), 70 deletions(-)

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 3370dab..92b4c49 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -52,6 +52,7 @@ const char *default_search_path[NR_SEARCH_PATH] = {
#define MAX_PATH_LEN 256
#define MAX_PROBES 128
#define MAX_PROBE_ARGS 128
+#define PERFPROBE_GROUP "perfprobe"

/* Session management structure */
static struct {
@@ -60,20 +61,100 @@ static struct {
int need_dwarf;
int nr_probe;
struct probe_point probes[MAX_PROBES];
- char *events[MAX_PROBES];
} session;

#define semantic_error(msg ...) die("Semantic error :" msg)

-/* Parse a probe point. Note that any error must die. */
-static void parse_probepoint(const char *str)
+/* Parse probe point. Return 1 if return probe */
+static void parse_probe_point(char *arg, struct probe_point *pp)
+{
+ char *ptr, *tmp;
+ char c, nc;
+ /*
+ * <Syntax>
+ * perf probe SRC:LN
+ * perf probe FUNC[+OFFS|%return][@SRC]
+ */
+
+ ptr = strpbrk(arg, ":+@%");
+ if (ptr) {
+ nc = *ptr;
+ *ptr++ = '\0';
+ }
+
+ /* Check arg is function or file and copy it */
+ if (strchr(arg, '.')) /* File */
+ pp->file = strdup(arg);
+ else /* Function */
+ pp->function = strdup(arg);
+ DIE_IF(pp->file == NULL && pp->function == NULL);
+
+ /* Parse other options */
+ while (ptr) {
+ arg = ptr;
+ c = nc;
+ ptr = strpbrk(arg, ":+@%");
+ if (ptr) {
+ nc = *ptr;
+ *ptr++ = '\0';
+ }
+ switch (c) {
+ case ':': /* Line number */
+ pp->line = strtoul(arg, &tmp, 0);
+ if (*tmp != '\0')
+ semantic_error("There is non-digit charactor"
+ " in line number.");
+ break;
+ case '+': /* Byte offset from a symbol */
+ pp->offset = strtoul(arg, &tmp, 0);
+ if (*tmp != '\0')
+ semantic_error("There is non-digit charactor"
+ " in offset.");
+ break;
+ case '@': /* File name */
+ if (pp->file)
+ semantic_error("SRC@SRC is not allowed.");
+ pp->file = strdup(arg);
+ DIE_IF(pp->file == NULL);
+ if (ptr)
+ semantic_error("@SRC must be the last "
+ "option.");
+ break;
+ case '%': /* Probe places */
+ if (strcmp(arg, "return") == 0) {
+ pp->retprobe = 1;
+ } else /* Others not supported yet */
+ semantic_error("%%%s is not supported.", arg);
+ break;
+ default:
+ DIE_IF("Program has a bug.");
+ break;
+ }
+ }
+
+ /* Exclusion check */
+ if (pp->line && pp->function)
+ semantic_error("Function-relative line number is not"
+ " supported yet.");
+ if (!pp->line && pp->file && !pp->function)
+ semantic_error("File always requires line number.");
+ if (pp->offset && !pp->function)
+ semantic_error("Offset requires an entry function.");
+ if (pp->retprobe && !pp->function)
+ semantic_error("Return probe requires an entry function.");
+ if (pp->offset && pp->retprobe)
+ semantic_error("Offset can't be used with return probe.");
+
+ pr_debug("symbol:%s file:%s line:%d offset:%d, return:%d\n",
+ pp->function, pp->file, pp->line, pp->offset, pp->retprobe);
+}
+
+/* Parse an event definition. Note that any error must die. */
+static void parse_probe_event(const char *str)
{
char *argv[MAX_PROBE_ARGS + 2]; /* Event + probe + args */
int argc, i;
- char *arg, *ptr;
struct probe_point *pp = &session.probes[session.nr_probe];
- char **event = &session.events[session.nr_probe];
- int retp = 0;

pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
if (++session.nr_probe == MAX_PROBES)
@@ -103,70 +184,28 @@ static void parse_probepoint(const char *str)
pr_debug("argv[%d]=%s\n", argc, argv[argc - 1]);
}
} while (*str != '\0');
- if (argc < 2)
- semantic_error("Need event-name and probe-point at least.");
-
- /* Parse the event name */
- if (argv[0][0] == 'r')
- retp = 1;
- else if (argv[0][0] != 'p')
- semantic_error("You must specify 'p'(kprobe) or"
- " 'r'(kretprobe) first.");
- /* TODO: check event name */
- *event = argv[0];
+ if (!argc)
+ semantic_error("An empty argument.");

/* Parse probe point */
- arg = argv[1];
- if (arg[0] == '@') {
- /* Source Line */
- arg++;
- ptr = strchr(arg, ':');
- if (!ptr || !isdigit(ptr[1]))
- semantic_error("Line number is required.");
- *ptr++ = '\0';
- if (strlen(arg) == 0)
- semantic_error("No file name.");
- pp->file = strdup(arg);
- pp->line = atoi(ptr);
- if (!pp->file || !pp->line)
- semantic_error("Failed to parse line.");
- pr_debug("file:%s line:%d\n", pp->file, pp->line);
- } else {
- /* Function name */
- ptr = strchr(arg, '+');
- if (ptr) {
- if (!isdigit(ptr[1]))
- semantic_error("Offset is required.");
- *ptr++ = '\0';
- pp->offset = atoi(ptr);
- } else
- ptr = arg;
- ptr = strchr(ptr, '@');
- if (ptr) {
- *ptr++ = '\0';
- pp->file = strdup(ptr);
- }
- pp->function = strdup(arg);
- pr_debug("symbol:%s file:%s offset:%d\n",
- pp->function, pp->file, pp->offset);
- }
- free(argv[1]);
+ parse_probe_point(argv[0], pp);
+ free(argv[0]);
if (pp->file)
session.need_dwarf = 1;

/* Copy arguments */
- pp->nr_args = argc - 2;
+ pp->nr_args = argc - 1;
if (pp->nr_args > 0) {
pp->args = (char **)malloc(sizeof(char *) * pp->nr_args);
if (!pp->args)
die("malloc");
- memcpy(pp->args, &argv[2], sizeof(char *) * pp->nr_args);
+ memcpy(pp->args, &argv[1], sizeof(char *) * pp->nr_args);
}

/* Ensure return probe has no C argument */
for (i = 0; i < pp->nr_args; i++)
if (is_c_varname(pp->args[i])) {
- if (retp)
+ if (pp->retprobe)
semantic_error("You can't specify local"
" variable for kretprobe");
session.need_dwarf = 1;
@@ -175,11 +214,11 @@ static void parse_probepoint(const char *str)
pr_debug("%d arguments\n", pp->nr_args);
}

-static int opt_add_probepoint(const struct option *opt __used,
+static int opt_add_probe_event(const struct option *opt __used,
const char *str, int unset __used)
{
if (str)
- parse_probepoint(str);
+ parse_probe_event(str);
return 0;
}

@@ -229,17 +268,16 @@ static const struct option options[] = {
#endif
OPT_CALLBACK('a', "add", NULL,
#ifdef NO_LIBDWARF
- "p|r:[GRP/]NAME FUNC[+OFFS] [ARG ...]",
+ "FUNC[+OFFS|%return] [ARG ...]",
#else
- "p|r:[GRP/]NAME FUNC[+OFFS][@SRC]|@SRC:LINE [ARG ...]",
+ "FUNC[+OFFS|%return][@SRC]|SRC:LINE [ARG ...]",
#endif
"probe point definition, where\n"
- "\t\tp:\tkprobe probe\n"
- "\t\tr:\tkretprobe probe\n"
"\t\tGRP:\tGroup name (optional)\n"
"\t\tNAME:\tEvent name\n"
"\t\tFUNC:\tFunction name\n"
"\t\tOFFS:\tOffset from function entry (in byte)\n"
+ "\t\t%return:\tPut the probe at function return\n"
#ifdef NO_LIBDWARF
"\t\tARG:\tProbe argument (only \n"
#else
@@ -248,7 +286,7 @@ static const struct option options[] = {
"\t\tARG:\tProbe argument (local variable name or\n"
#endif
"\t\t\tkprobe-tracer argument format is supported.)\n",
- opt_add_probepoint),
+ opt_add_probe_event),
OPT_END()
};

@@ -266,7 +304,7 @@ static int write_new_event(int fd, const char *buf)

#define MAX_CMDLEN 256

-static int synthesize_probepoint(struct probe_point *pp)
+static int synthesize_probe_event(struct probe_point *pp)
{
char *buf;
int i, len, ret;
@@ -316,12 +354,12 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
/* Synthesize probes without dwarf */
for (j = 0; j < session.nr_probe; j++) {
#ifndef NO_LIBDWARF
- if (session.events[j][0] != 'r') {
+ if (!session.probes[j].retprobe) {
session.need_dwarf = 1;
continue;
}
#endif
- ret = synthesize_probepoint(&session.probes[j]);
+ ret = synthesize_probe_event(&session.probes[j]);
if (ret == -E2BIG)
semantic_error("probe point is too long.");
else if (ret < 0)
@@ -349,7 +387,6 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
ret = find_probepoint(fd, pp);
if (ret <= 0)
die("No probe point found.\n");
- pr_debug("probe event %s found\n", session.events[j]);
}
close(fd);

@@ -364,13 +401,17 @@ setup_probes:
for (j = 0; j < session.nr_probe; j++) {
pp = &session.probes[j];
if (pp->found == 1) {
- snprintf(buf, MAX_CMDLEN, "%s %s\n",
- session.events[j], pp->probes[0]);
+ snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x %s\n",
+ pp->retprobe ? 'r' : 'p', PERFPROBE_GROUP,
+ pp->function, pp->offset, pp->probes[0]);
write_new_event(fd, buf);
} else
for (i = 0; i < pp->found; i++) {
- snprintf(buf, MAX_CMDLEN, "%s%d %s\n",
- session.events[j], i, pp->probes[i]);
+ snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x_%d %s\n",
+ pp->retprobe ? 'r' : 'p',
+ PERFPROBE_GROUP,
+ pp->function, pp->offset, i,
+ pp->probes[0]);
write_new_event(fd, buf);
}
}
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index b98d35e..6d3bac9 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -483,10 +483,20 @@ static void show_probepoint(Dwarf_Die sp_die, Dwarf_Signed offs,
if (ret == DW_DLV_OK) {
ret = snprintf(tmp, MAX_PROBE_BUFFER, "%s+%u", name,
(unsigned int)offs);
+ /* Copy the function name if possible */
+ if (!pp->function) {
+ pp->function = strdup(name);
+ pp->offset = offs;
+ }
dwarf_dealloc(__dw_debug, name, DW_DLA_STRING);
} else {
/* This function has no name. */
ret = snprintf(tmp, MAX_PROBE_BUFFER, "0x%llx", pf->addr);
+ if (!pp->function) {
+ /* TODO: Use _stext */
+ pp->function = strdup("");
+ pp->offset = (int)pf->addr;
+ }
}
DIE_IF(ret < 0);
DIE_IF(ret >= MAX_PROBE_BUFFER);
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index d17fafc..240d6cb 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -22,6 +22,8 @@ struct probe_point {
int nr_args; /* Number of arguments */
char **args; /* Arguments */

+ int retprobe; /* Return probe */
+
/* Output */
int found; /* Number of found probe points */
char *probes[MAX_PROBES]; /* Output buffers (will be allocated)*/

--
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com


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