RE: [PATCH RFC V8 3/4] perf,tools: per-event callgraph support

[Liang, Kan]

> > +	/* User explicitly set per-event callgraph, clear the old setting and
> reset. */
> > +	if ((callgraph_buf != NULL) || (dump_size > 0)) {
> > +
> > +		/* parse callgraph parameters */
> > +		if (callgraph_buf != NULL) {
> > +			if (!strcmp(callgraph_buf, "no")) {
> > +				param.enabled = false;
> > +				param.record_mode = CALLCHAIN_NONE;
> > +			} else {
> > +				param.enabled = true;
> > +				if
> (parse_callchain_record_opt(callgraph_buf, &param)) {
> > +					pr_err("per-event callgraph setting
> for %s failed. "
> > +					       "Apply callgraph global setting
> for it\n",
> > +					       evsel->name);
> > +					return;
> 
> hum, calling parse_callchain_record_opt from evsel hurts the python code:
> 
> 17: Try 'import perf' in python, checking link problems      :
> --- start ---
> test child forked, pid 25751
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
> ImportError: python/perf.so: undefined symbol:
> parse_callchain_record_opt test child finished with -1
> ---- end ----
> Try 'import perf' in python, checking link problems: FAILED!
> 
> 
> not sure if we can call it from some place else (I guess not), then we'd need
> to either put the util/callchain.c under python objects,

We cannot only put the util/callchain.c under python objects, since
there are too many dependency for callchain.c. 

> or somehow refine
> needed parsing code..

Could we just move the related code to util.c as below?

---
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 931cca8..773fe13 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -25,96 +25,9 @@
 
 __thread struct callchain_cursor callchain_cursor;
 
-#ifdef HAVE_DWARF_UNWIND_SUPPORT
-static int get_stack_size(const char *str, unsigned long *_size)
-{
-	char *endptr;
-	unsigned long size;
-	unsigned long max_size = round_down(USHRT_MAX, sizeof(u64));
-
-	size = strtoul(str, &endptr, 0);
-
-	do {
-		if (*endptr)
-			break;
-
-		size = round_up(size, sizeof(u64));
-		if (!size || size > max_size)
-			break;
-
-		*_size = size;
-		return 0;
-
-	} while (0);
-
-	pr_err("callchain: Incorrect stack dump size (max %ld): %s\n",
-	       max_size, str);
-	return -1;
-}
-#endif /* HAVE_DWARF_UNWIND_SUPPORT */
-
 int parse_callchain_record_opt(const char *arg, struct callchain_param *param)
 {
-	char *tok, *name, *saveptr = NULL;
-	char *buf;
-	int ret = -1;
-
-	/* We need buffer that we know we can write to. */
-	buf = malloc(strlen(arg) + 1);
-	if (!buf)
-		return -ENOMEM;
-
-	strcpy(buf, arg);
-
-	tok = strtok_r((char *)buf, ",", &saveptr);
-	name = tok ? : (char *)buf;
-
-	do {
-		/* Framepointer style */
-		if (!strncmp(name, "fp", sizeof("fp"))) {
-			if (!strtok_r(NULL, ",", &saveptr)) {
-				param->record_mode = CALLCHAIN_FP;
-				ret = 0;
-			} else
-				pr_err("callchain: No more arguments "
-				       "needed for --call-graph fp\n");
-			break;
-
-#ifdef HAVE_DWARF_UNWIND_SUPPORT
-		/* Dwarf style */
-		} else if (!strncmp(name, "dwarf", sizeof("dwarf"))) {
-			const unsigned long default_stack_dump_size = 8192;
-
-			ret = 0;
-			param->record_mode = CALLCHAIN_DWARF;
-			param->dump_size = default_stack_dump_size;
-
-			tok = strtok_r(NULL, ",", &saveptr);
-			if (tok) {
-				unsigned long size = 0;
-
-				ret = get_stack_size(tok, &size);
-				param->dump_size = size;
-			}
-#endif /* HAVE_DWARF_UNWIND_SUPPORT */
-		} else if (!strncmp(name, "lbr", sizeof("lbr"))) {
-			if (!strtok_r(NULL, ",", &saveptr)) {
-				param->record_mode = CALLCHAIN_LBR;
-				ret = 0;
-			} else
-				pr_err("callchain: No more arguments "
-					"needed for --call-graph lbr\n");
-			break;
-		} else {
-			pr_err("callchain: Unknown --call-graph option "
-			       "value: %s\n", arg);
-			break;
-		}
-
-	} while (0);
-
-	free(buf);
-	return ret;
+	return parse_callchain_record(arg, param);
 }
 
 static int parse_callchain_mode(const char *value)
diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index 68a32c2..acee2b3 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -177,6 +177,7 @@ int fill_callchain_info(struct addr_location *al, struct callchain_cursor_node *
 			bool hide_unresolved);
 
 extern const char record_callchain_help[];
+extern int parse_callchain_record(const char *arg, struct callchain_param *param);
 int parse_callchain_record_opt(const char *arg, struct callchain_param *param);
 int parse_callchain_report_opt(const char *arg);
 int perf_callchain_config(const char *var, const char *value);
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 106cd20..675d237 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -651,7 +651,7 @@ static void apply_config_terms(struct perf_evsel *evsel,
 				param.record_mode = CALLCHAIN_NONE;
 			} else {
 				param.enabled = true;
-				if (parse_callchain_record_opt(callgraph_buf, &param)) {
+				if (parse_callchain_record(callgraph_buf, &param)) {
 					pr_err("per-event callgraph setting for %s failed. "
 					       "Apply callgraph global setting for it\n",
 					       evsel->name);
diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index edc2d63..f7adf12 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -566,6 +566,96 @@ unsigned long parse_tag_value(const char *str, struct parse_tag *tags)
 	return (unsigned long) -1;
 }
 
+int get_stack_size(const char *str, unsigned long *_size)
+{
+	char *endptr;
+	unsigned long size;
+	unsigned long max_size = round_down(USHRT_MAX, sizeof(u64));
+
+	size = strtoul(str, &endptr, 0);
+
+	do {
+		if (*endptr)
+			break;
+
+		size = round_up(size, sizeof(u64));
+		if (!size || size > max_size)
+			break;
+
+		*_size = size;
+		return 0;
+
+	} while (0);
+
+	pr_err("callchain: Incorrect stack dump size (max %ld): %s\n",
+	       max_size, str);
+	return -1;
+}
+
+int parse_callchain_record(const char *arg, struct callchain_param *param)
+{
+	char *tok, *name, *saveptr = NULL;
+	char *buf;
+	int ret = -1;
+
+	/* We need buffer that we know we can write to. */
+	buf = malloc(strlen(arg) + 1);
+	if (!buf)
+		return -ENOMEM;
+
+	strcpy(buf, arg);
+
+	tok = strtok_r((char *)buf, ",", &saveptr);
+	name = tok ? : (char *)buf;
+
+	do {
+		/* Framepointer style */
+		if (!strncmp(name, "fp", sizeof("fp"))) {
+			if (!strtok_r(NULL, ",", &saveptr)) {
+				param->record_mode = CALLCHAIN_FP;
+				ret = 0;
+			} else
+				pr_err("callchain: No more arguments "
+				       "needed for --call-graph fp\n");
+			break;
+
+#ifdef HAVE_DWARF_UNWIND_SUPPORT
+		/* Dwarf style */
+		} else if (!strncmp(name, "dwarf", sizeof("dwarf"))) {
+			const unsigned long default_stack_dump_size = 8192;
+
+			ret = 0;
+			param->record_mode = CALLCHAIN_DWARF;
+			param->dump_size = default_stack_dump_size;
+
+			tok = strtok_r(NULL, ",", &saveptr);
+			if (tok) {
+				unsigned long size = 0;
+
+				ret = get_stack_size(tok, &size);
+				param->dump_size = size;
+			}
+#endif /* HAVE_DWARF_UNWIND_SUPPORT */
+		} else if (!strncmp(name, "lbr", sizeof("lbr"))) {
+			if (!strtok_r(NULL, ",", &saveptr)) {
+				param->record_mode = CALLCHAIN_LBR;
+				ret = 0;
+			} else
+				pr_err("callchain: No more arguments "
+					"needed for --call-graph lbr\n");
+			break;
+		} else {
+			pr_err("callchain: Unknown --call-graph option "
+			       "value: %s\n", arg);
+			break;
+		}
+
+	} while (0);
+
+	free(buf);
+	return ret;
+}
+
 int filename__read_str(const char *filename, char **buf, size_t *sizep)
 {
 	size_t size = 0, alloc_size = 0;
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index 20d625a..8148703 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -351,4 +351,6 @@ static inline char *asprintf_expr_not_in_ints(const char *var, size_t nints, int
 	return asprintf_expr_inout_ints(var, false, nints, ints);
 }
 
+int get_stack_size(const char *str, unsigned long *_size);
+
 #endif /* GIT_COMPAT_UTIL_H */
 --

Thanks,
Kan

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