[PATCH 1/2] perfcounters: Fix build for tracepoint profiling

[PATCH 1/2] perfcounters: Fix build for tracepoint profiling

[Chris Wilson]

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 init/Kconfig          |    2 +-
 kernel/perf_counter.c |   10 +++-------
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index 0e8784e..13473ac 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -955,7 +955,7 @@ config PERF_COUNTERS
 
 config EVENT_PROFILE
 	bool "Tracepoint profile sources"
-	depends on PERF_COUNTERS && EVENT_TRACER
+	depends on PERF_COUNTERS && EVENT_TRACING
 	default y
 
 endmenu
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index d55a50d..c6c38fb 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -3671,7 +3671,7 @@ static const struct pmu perf_ops_task_clock = {
 void perf_tpcounter_event(int event_id)
 {
 	struct perf_sample_data data = {
-		.regs = get_irq_regs();
+		.regs = get_irq_regs(),
 		.addr = 0,
 	};
 
@@ -3687,16 +3687,12 @@ extern void ftrace_profile_disable(int);
 
 static void tp_perf_counter_destroy(struct perf_counter *counter)
 {
-	ftrace_profile_disable(perf_event_id(&counter->attr));
+	ftrace_profile_disable(counter->attr.config);
 }
 
 static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
 {
-	int event_id = perf_event_id(&counter->attr);
-	int ret;
-
-	ret = ftrace_profile_enable(event_id);
-	if (ret)
+	if (ftrace_profile_enable(counter->attr.config))
 		return NULL;
 
 	counter->destroy = tp_perf_counter_destroy;
-- 
1.6.3.3

[PATCH 2/2] perf tool: Add a trace point event parser.

[Chris Wilson]

Accept events of the form tp=i915/i915_wait and convert those to the
ftrace event id by expanding the short name to
'/sys/kernel/debug/tracing/events/i915/i915_wait/id'. (Substituting the
real debugfs mount path as appropriate.)

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 tools/perf/util/parse-events.c |  133 +++++++++++++++++++++++++++++++++++++++-
 1 files changed, 131 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 5184959..36078a6 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1,11 +1,12 @@
-
-#include "../perf.h"
 #include "util.h"
+#include "../perf.h"
 #include "parse-options.h"
 #include "parse-events.h"
 #include "exec_cmd.h"
 #include "string.h"
 
+#include <sys/mount.h>
+
 extern char *strcasestr(const char *haystack, const char *needle);
 
 int					nr_counters;
@@ -339,6 +340,133 @@ parse_numeric_event(const char **strp, struct perf_counter_attr *attr)
 	return 0;
 }
 
+/* mini /proc/mounts parser: searching for "^blah /mount/point debugfs" */
+static const char *
+debug_mntpt (void)
+{
+	static char mntpt[4096];
+	FILE *file;
+	size_t line_len;
+	char *line;
+
+	if (mntpt[0])
+		return mntpt;
+
+	file = fopen("/proc/mounts", "r");
+	if (file == NULL)
+		return NULL;
+
+	while (getline(&line, &line_len, file) >= 0) {
+		char *start, *end;
+
+		if (strstr(line, " debugfs ") == NULL)
+			continue;
+
+		start = strchr(line, ' ') + 1;
+		end = strchr(start + 1, ' ');
+		if(end - start > 4095)
+			goto err_file;
+		memcpy(mntpt, start, end-start);
+		break;
+	}
+	free(line);
+	fclose(file);
+
+	if (mntpt[0] == '\0') {
+		if (mount("none", "/sys/kernel/debug", "debugfs", 0, NULL))
+			return NULL;
+
+		strcpy(mntpt, "/sys/kernel/debug");
+	}
+
+	return mntpt;
+
+err_file:
+	free(line);
+	fclose(file);
+	return NULL;
+}
+
+static int
+safe_strcat(char **strp, int *rem, const char *src, int len)
+{
+	if (len < 0)
+		len = strlen(src);
+	if (len >= *rem)
+		return 0;
+
+	memcpy(*strp, src, len);
+	*strp += len;
+	*rem -= len;
+	**strp = '\0';
+
+	return 1;
+}
+
+static int
+parse_tracepoint_event(const char **strp, struct perf_counter_attr *attr)
+{
+	const char *str = *strp;
+	const char *mntpt;
+	char buf[4096], *bufp;
+	int rem;
+	int fd;
+	int ret;
+	char *comma;
+
+	if (strncmp(str, "tp=", 3))
+	    return 0;
+
+	str += 3;
+
+	/* Expand the tracepoint event to:
+	 *   /sys/kernel/debug/tracing/events/<tracepoint>/id
+	 * and then read that file to determine the ftrace event id to
+	 * pass to perf_counters. Substituting the real debugfs mount path
+	 * as appropriate.
+	 */
+
+	mntpt = debug_mntpt();
+	if (mntpt == NULL)
+		return 0;
+
+	bufp = buf, rem = sizeof(buf);
+	if (!safe_strcat(&bufp, &rem, mntpt, -1))
+		return 0;
+	if (!safe_strcat(&bufp, &rem, "/tracing/events/", -1))
+		return 0;
+
+	comma = strchr(str, ',');
+	if (comma) {
+		if (!safe_strcat(&bufp, &rem, str, comma - str))
+			return 0;
+		*strp = comma;
+	} else {
+		if (!safe_strcat(&bufp, &rem, str, -1))
+			return 0;
+		*strp = str + strlen (str);
+	}
+	if (!safe_strcat(&bufp, &rem, "/id", -1))
+		return 0;
+
+	fd = open(buf, O_RDONLY);
+	if (fd == 0)
+		return 0;
+
+	/* We expect to read a string of "integer\n". */
+	ret = read(fd, buf, sizeof(buf));
+	close(fd);
+	if (ret == -1 || ret == sizeof(buf))
+		return 0;
+
+	buf[ret] = '\0';
+
+	attr->config = strtoul(buf, &bufp, 0);
+	attr->type = PERF_TYPE_TRACEPOINT;
+
+	return bufp == buf + ret-1;
+}
+
 static int
 parse_event_modifier(const char **strp, struct perf_counter_attr *attr)
 {
@@ -377,6 +505,7 @@ static int parse_event_symbols(const char **str, struct perf_counter_attr *attr)
 	if (!(parse_raw_event(str, attr) ||
 	      parse_numeric_event(str, attr) ||
 	      parse_symbolic_event(str, attr) ||
+	      parse_tracepoint_event(str, attr) ||
 	      parse_generic_hw_event(str, attr)))
 		return 0;
 
-- 
1.6.3.3

Re: [PATCH 2/2] perf tool: Add a trace point event parser.

[Ingo Molnar]

* Chris Wilson <chris@chris-wilson.co.uk> wrote:

> Accept events of the form tp=i915/i915_wait and convert those to the
> ftrace event id by expanding the short name to
> '/sys/kernel/debug/tracing/events/i915/i915_wait/id'. (Substituting the
> real debugfs mount path as appropriate.)
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  tools/perf/util/parse-events.c |  133 +++++++++++++++++++++++++++++++++++++++-
>  1 files changed, 131 insertions(+), 2 deletions(-)

Ok - this looks useful. Mind working with Jason Baron (Cc:-ed) who 
incidentally posted a similar series on some joint solution?

Thanks,

	Ingo

[tip:perfcounters/urgent] perf_counter: Fix the tracepoint channel to perfcounters

[tip-bot for Chris Wilson]

Commit-ID:  d4d7d0b9545721d3cabb19d15163bbc66b797707
Gitweb:     http://git.kernel.org/tip/d4d7d0b9545721d3cabb19d15163bbc66b797707
Author:     Chris Wilson <chris@chris-wilson.co.uk>
AuthorDate: Mon, 6 Jul 2009 09:31:33 +0100
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Mon, 13 Jul 2009 09:23:10 +0200

perf_counter: Fix the tracepoint channel to perfcounters

Fix a missed rename in EVENT_PROFILE support so that it gets
built and allows tracepoint tracing from the 'perf' tool.

Fix a typo in the (never before built & enabled) portion in
perf_counter.c as well, and update that code to the
attr.config changes as well.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Gamari <bgamari.foss@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1246869094-21237-1-git-send-email-chris@chris-wilson.co.uk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


---
 init/Kconfig          |    2 +-
 kernel/perf_counter.c |   10 +++-------
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index 1ce05a4..cb2c092 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -962,7 +962,7 @@ config PERF_COUNTERS
 
 config EVENT_PROFILE
 	bool "Tracepoint profile sources"
-	depends on PERF_COUNTERS && EVENT_TRACER
+	depends on PERF_COUNTERS && EVENT_TRACING
 	default y
 
 endmenu
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index d55a50d..c6c38fb 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -3671,7 +3671,7 @@ static const struct pmu perf_ops_task_clock = {
 void perf_tpcounter_event(int event_id)
 {
 	struct perf_sample_data data = {
-		.regs = get_irq_regs();
+		.regs = get_irq_regs(),
 		.addr = 0,
 	};
 
@@ -3687,16 +3687,12 @@ extern void ftrace_profile_disable(int);
 
 static void tp_perf_counter_destroy(struct perf_counter *counter)
 {
-	ftrace_profile_disable(perf_event_id(&counter->attr));
+	ftrace_profile_disable(counter->attr.config);
 }
 
 static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
 {
-	int event_id = perf_event_id(&counter->attr);
-	int ret;
-
-	ret = ftrace_profile_enable(event_id);
-	if (ret)
+	if (ftrace_profile_enable(counter->attr.config))
 		return NULL;
 
 	counter->destroy = tp_perf_counter_destroy;