This change adds a --clock option to trace-cmd record. It simply writes
trace_clock on debugfs. Examples of valid choices on most systems are: local,
global, counter, and any other choice compatible with ftrace.
This complements Yoshihiro Yunomae's change 8c9867c (trace-cmd: Add support for
extracting trace_clock in report).
Signed-off-by: Ian Webster <i...@planetaryresources.com>
---
Changes per Steven's comments:
* add missing const
* preserve tab whitespace
Documentation/trace-cmd-record.1.txt | 5 +++++
trace-record.c | 19 +++++++++++++++++++
trace-usage.c | 1 +
3 files changed, 25 insertions(+)
diff --git a/Documentation/trace-cmd-record.1.txt
b/Documentation/trace-cmd-record.1.txt
index 832a257..5e83454 100644
--- a/Documentation/trace-cmd-record.1.txt
+++ b/Documentation/trace-cmd-record.1.txt
@@ -240,6 +240,11 @@ OPTIONS
timestamp to gettimeofday which will allow wall time output from the
timestamps reading the created 'trace.dat' file.
+*--clock* 'clock_name'::
+ When an event is recorded into the ring buffer, a timestamp is added. This
+ stamp comes from the specified clock. Ftrace uses the "local" clock by
+ default. Other common clocks include: global, counter, uptime, perf,
x86-tsc.
+
EXAMPLES
--------
diff --git a/trace-record.c b/trace-record.c
index 0199627..2143080 100644
--- a/trace-record.c
+++ b/trace-record.c
@@ -399,6 +399,20 @@ static int set_ftrace(int set, int use_proc)
return 0;
}
+static void set_trace_clock(const char *clock_choice)
+{
+ FILE *fp;
+ char *path;
+
+ path = tracecmd_get_tracing_file("trace_clock");
+ fp = fopen(path, "w");
+ if (!fp)
+ die("writing to '%s'", path);
+ tracecmd_put_tracing_file(path);
+ fwrite(clock_choice, 1, strlen(clock_choice), fp);
+ fclose(fp);
+}
+
static char *
get_instance_file(struct buffer_instance *instance, const char *file)
{
@@ -2279,6 +2293,7 @@ static void record_all_events(void)
}
enum {
+ OPT_clock = 252,
OPT_nosplice = 253,
OPT_funcstack = 254,
OPT_date = 255,
@@ -2351,6 +2366,7 @@ void trace_record (int argc, char **argv)
{"func-stack", no_argument, NULL, OPT_funcstack},
{"nosplice", no_argument, NULL, OPT_nosplice},
{"help", no_argument, NULL, '?'},
+ {"clock", required_argument, NULL, OPT_clock},
{NULL, 0, NULL, 0}
};
@@ -2530,6 +2546,9 @@ void trace_record (int argc, char **argv)
case OPT_nosplice:
recorder_flags |= TRACECMD_RECORD_NOSPLICE;
break;
+ case OPT_clock:
+ set_trace_clock(optarg);
+ break;
default:
usage(argv);
}
diff --git a/trace-usage.c b/trace-usage.c
index b8f26e6..54dbb85 100644
--- a/trace-usage.c
+++ b/trace-usage.c
@@ -46,6 +46,7 @@ static struct usage_help usage_help[] = {
" -i do not fail if an event is not found\n"
" --func-stack perform a stack trace for function
tracer\n"
" (use with caution)\n"
+ " --clock change the method used to produce trace
timestamps\n"
},
{
"start",
--
1.7.9.5
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