[PATCH 05/12] trace-cmd: Save information for tsc to nanoseconds conversion in trace file

From: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
To: rostedt@goodmis.org
Cc: linux-trace-devel@vger.kernel.org
Subject: [PATCH 05/12] trace-cmd: Save information for tsc to nanoseconds conversion in trace file
Date: Mon, 15 Mar 2021 08:18:25 +0200	[thread overview]
Message-ID: <20210315061832.168495-6-tz.stoyanov@gmail.com> (raw)
In-Reply-To: <20210315061832.168495-1-tz.stoyanov@gmail.com>

Store multiplier and shift, required for TSC clock to nanosecond
conversion in the metadata of the trace file.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 tracecmd/trace-record.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index b064a1ff..30d3ed89 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -666,6 +666,17 @@ static void delete_thread_data(void)
 	}
 }
 
+static void
+add_tsc2nsec(struct tracecmd_output *handle, struct buffer_instance *instance)
+{
+	int array[] = { instance->tsc2nsec.mult,
+			instance->tsc2nsec.shift,
+			instance->tsc2nsec.offset};
+
+	tracecmd_add_option(handle, TRACECMD_OPTION_TSC2NSEC,
+			    sizeof(array), array);
+}
+
 static void host_tsync_complete(struct buffer_instance *instance)
 {
 	struct tracecmd_output *handle = NULL;
@@ -680,6 +691,16 @@ static void host_tsync_complete(struct buffer_instance *instance)
 		handle = tracecmd_get_output_handle_fd(fd);
 		if (!handle)
 			die("cannot create output handle");
+
+		/*
+		 * If TSC is used as current trace clock and there is
+		 * information for tsc to nanosecond conversion, store it
+		 * in the trace file
+		 */
+		if (instance->tsc2nsec.mult && instance->clock &&
+		    !strncmp(top_instance.clock, TSC_CLOCK, strlen(TSC_CLOCK)))
+			add_tsc2nsec(handle, instance);
+
 		tracecmd_write_guest_time_shift(handle, instance->tsync);
 		tracecmd_append_options(handle);
 		tracecmd_output_close(handle);
@@ -4269,6 +4290,15 @@ static void record_data(struct common_record_context *ctx)
 				add_guest_info(handle, instance);
 		}
 
+		/*
+		 * If  TSC is used as current trace clock and there is
+		 * information for tsc to nanosecond conversion, store it
+		 * in the trace file
+		 */
+		if (top_instance.tsc2nsec.mult && top_instance.clock &&
+		    !strncmp(top_instance.clock, TSC_CLOCK, strlen(TSC_CLOCK)))
+			add_tsc2nsec(handle, &top_instance);
+
 		if (tracecmd_write_cmdlines(handle))
 			die("Writing cmdlines");
 
-- 
2.29.2

