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Date: Mon, 6 Jul 2009 09:31:34 +0100
From: Chris Wilson <chris@...is-wilson.co.uk>
To: Ingo Molnar <mingo@...e.hu>
Cc: Chris Wilson <chris@...is-wilson.co.uk>,
Ben Gamari <bgamari.foss@...il.com>,
<linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] perf tool: Add a trace point event parser.
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@...is-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
--
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