[LTP] [PATCH 6/6] sched_football: Add trace_marker messages if we're tracing

[Cyril Hrubis]

Hi!
> Cc: kernel-team@android.com
> Cc: Darren Hart <darren@os.amperecomputing.com>
> Signed-off-by: John Stultz <jstultz@google.com>
> ---
>  .../realtime/func/sched_football/sched_football.c    | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/testcases/realtime/func/sched_football/sched_football.c b/testcases/realtime/func/sched_football/sched_football.c
> index 45fbf6766..ca44584b0 100644
> --- a/testcases/realtime/func/sched_football/sched_football.c
> +++ b/testcases/realtime/func/sched_football/sched_football.c
> @@ -67,6 +67,7 @@
>  #include <pthread.h>
>  #include <sched.h>
>  #include <errno.h>
> +#include <fcntl.h>
>  #include <sys/syscall.h>
>  #include <unistd.h>
>  #include <sys/prctl.h>
> @@ -167,10 +168,14 @@ void *thread_offense(void *arg)
>  	return NULL;
>  }
>  
> +#define BUF_LEN 256
>  int referee(int game_length)
>  {
>  	struct timeval start, now;
> +	char buf[BUF_LEN];
>  	int final_ball;
> +	int fd = open("/sys/kernel/tracing/trace_marker", O_RDWR, 0);
> +	int ret;
>  
>  	prctl(PR_SET_NAME, "referee", 0, 0, 0);
>  	printf("Game On (%d seconds)!\n", game_length);
> @@ -178,14 +183,19 @@ int referee(int game_length)
>  	gettimeofday(&start, NULL);
>  	now = start;
>  
> +	sprintf(buf, "I|%i|Game_Started!\n", getpid());
>  	/* Start the game! */
>  	atomic_set(0, &the_ball);
> -
> +	if (fd > 0)
> +		ret = write(fd, buf, strnlen(buf, BUF_LEN));
>  	/* Watch the game */
>  	while ((now.tv_sec - start.tv_sec) < game_length) {
>  		sleep(1);
>  		gettimeofday(&now, NULL);
>  	}
> +	sprintf(buf, "I|%i|Game_Over!\n", getpid());
> +	if (fd > 0)
> +		ret = write(fd, buf, strnlen(buf, BUF_LEN));

I know that we havre only two usages now, but it would be a bit cleaner
and readable to have a function to print the messages, e.g.

static void tracer_write(const char *msg);

And we would do:

	tracer_write("Game_Started!");

It would be a good idea to add the test name to the message as well,
maybe as:

	sprintf(buf, "sched_football|%i|%s\n", getpid(), msg);

>  	final_ball = atomic_get(&the_ball);
>  	/* Blow the whistle */
>  	printf("Game Over!\n");
> -- 
> 2.44.0.769.g3c40516874-goog
> 
> 
> -- 
> Mailing list info: https://lists.linux.it/listinfo/ltp

-- 
Cyril Hrubis
chrubis@suse.cz