[PATCH v18 14/18] trace-cmd: Add host trace clock as guest trace argument

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx>]

When tracing host and guest machines, both should use the same
tracing clock for event timestamps. If a clock is specified
as host tracing argument, with option "-C clock_name", the same
is injected as guest tracing argument. If the user wants to use
different tracing clocks, it can specify it using "-C clock_name"
as guest tracing argument. In that case, the one specified by
the user has higher priority.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
---
 tracecmd/include/trace-local.h |  1 +
 tracecmd/trace-record.c        | 24 ++++++++++++++++++++++--
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index 90933cc..4c8d6cb 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -165,6 +165,7 @@ enum buffer_instance_flags {
 	BUFFER_FL_PROFILE	= 1 << 1,
 	BUFFER_FL_GUEST		= 1 << 2,
 	BUFFER_FL_AGENT		= 1 << 3,
+	BUFFER_FL_HAS_CLOCK	= 1 << 4,
 };
 
 struct func_list {
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index e4e2d63..51b40ff 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -5405,6 +5405,8 @@ static void parse_record_options(int argc,
 	char *sav;
 	int name_counter = 0;
 	int neg_event = 0;
+	struct buffer_instance *instance;
+	bool guest_sync_set = false;
 
 	init_common_record_context(ctx, curr_cmd);
 
@@ -5448,6 +5450,8 @@ static void parse_record_options(int argc,
 		 */
 		if (c != 'B' && c != 'A' && is_guest(ctx->instance)) {
 			add_arg(ctx->instance, c, opts, long_options, optarg);
+			if (c == 'C')
+				ctx->instance->flags |= BUFFER_FL_HAS_CLOCK;
 			continue;
 		}
 
@@ -5562,6 +5566,9 @@ static void parse_record_options(int argc,
 			break;
 		case 'C':
 			tracecmd_alloc_instance_clock(ctx->instance->ftrace, optarg);
+			ctx->instance->flags |= BUFFER_FL_HAS_CLOCK;
+			if (is_top_instance(ctx->instance))
+				guest_sync_set = true;
 			break;
 		case 'v':
 			neg_event = 1;
@@ -5779,14 +5786,27 @@ static void parse_record_options(int argc,
 
 	/* If --date is specified, prepend it to all guest VM flags */
 	if (ctx->date) {
-		struct buffer_instance *instance;
-
 		for_all_instances(instance) {
 			if (is_guest(instance))
 				add_argv(instance, "--date", true);
 		}
 	}
 
+	if (guest_sync_set) {
+		/* If -C is specified, prepend clock to all guest VM flags */
+		for_all_instances(instance) {
+			if (tracecmd_get_instance_clock(top_instance.ftrace)) {
+				if (is_guest(instance) &&
+				    !(instance->flags & BUFFER_FL_HAS_CLOCK)) {
+					add_argv(instance,
+						 tracecmd_get_instance_clock(top_instance.ftrace),
+						 true);
+					add_argv(instance, "-C", true);
+				}
+			}
+		}
+	}
+
 	if (!ctx->filtered && ctx->instance->filter_mod)
 		add_func(&ctx->instance->filter_funcs,
 			 ctx->instance->filter_mod, "*");
-- 
2.23.0