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[3/4] trace-cmd: Document --tsc2nsec option

Message ID 20210329125821.97496-4-tz.stoyanov@gmail.com (mailing list archive)
State Accepted
Headers show
Series Documented new trace-cmd options | expand

Commit Message

Tzvetomir Stoyanov (VMware) March 29, 2021, 12:58 p.m. UTC
Document the "trace-cmd record --tsc2nsec" option.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 Documentation/trace-cmd/trace-cmd-record.1.txt | 5 +++++
 tracecmd/trace-usage.c                         | 2 ++
 2 files changed, 7 insertions(+)
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Patch

diff --git a/Documentation/trace-cmd/trace-cmd-record.1.txt b/Documentation/trace-cmd/trace-cmd-record.1.txt
index 643659ad..d992002e 100644
--- a/Documentation/trace-cmd/trace-cmd-record.1.txt
+++ b/Documentation/trace-cmd/trace-cmd-record.1.txt
@@ -349,6 +349,11 @@  OPTIONS
         at the beginning and at the end of the trace.
         Timestamps synchronization with guests works only if there is support for VSOCK.\n"
 
+*--tsc2nsec*::
+    Convert the current clock to nanoseconds, using tsc multiplier and shift from the Linux
+        kernel's perf interface. This option does not change the trace clock, just assumes that
+        the tsc multiplier and shift are applicable for the selected clock. You may use the
+        "-C tsc2nsec" clock, if not sure what clock to select.
 *--stderr*::
     Have output go to stderr instead of stdout, but the output of the command
     executed will not be changed. This is useful if you want to monitor the
diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c
index 22537d20..386e88fe 100644
--- a/tracecmd/trace-usage.c
+++ b/tracecmd/trace-usage.c
@@ -62,6 +62,8 @@  static struct usage_help usage_help[] = {
 		"          --no-filter include trace-cmd threads in the trace\n"
 		"          --proc-map save the traced processes address map into the trace.dat file\n"
 		"          --user execute the specified [command ...] as given user\n"
+		"          --tsc2nsec Convert the current clock to nanoseconds, using tsc multiplier and shift from the Linux"
+		"               kernel's perf interface\n"
 		"          --tsync-interval set the loop interval, in ms, for timestamps synchronization with guests:"
 		"               If a negative number is specified, timestamps synchronization is disabled"
 		"               If 0 is specified, no loop is performed - timestamps offset is calculated only twice,"