[LTP] [PATCH] sched_football: isolcpus handling

[LTP] [PATCH] sched_football: isolcpus handling

[Attila Fazekas]

sched_football expects each player thread is scheduleable
to all of the physical CPU threads, however for example
when you are using isolcpus by default you threads are
not scheduled to some CPU. It leads to the test hangs.
591c56b045b2d44a0f4ba1a13545420b23e909b5solved was asimilar issue
in realtime/prio-preempt .

Signed-off-by: Attila Fazekas <afazekas@redhat.com>
---
 .../realtime/func/sched_football/sched_football.c  | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/testcases/realtime/func/sched_football/sched_football.c b/testcases/realtime/func/sched_football/sched_football.c
index 763b41f23..e4ae6a027 100644
--- a/testcases/realtime/func/sched_football/sched_football.c
+++ b/testcases/realtime/func/sched_football/sched_football.c
@@ -133,6 +133,18 @@ void referee(int game_length)
 	TST_EXP_EXPR(final_ball == 0);
 }
 
+static inline int get_numcpus(void)
+{
+	cpu_set_t mask;
+
+	CPU_ZERO(&mask);
+
+	/* Get the number of cpus accessible to the current process */
+	sched_getaffinity(getpid(), sizeof(mask), &mask);
+
+	return CPU_COUNT(&mask);
+}
+
 static void do_test(void)
 {
 	struct sched_param param;
@@ -140,7 +152,7 @@ static void do_test(void)
 	int i;
 
 	if (players_per_team == 0)
-		players_per_team = sysconf(_SC_NPROCESSORS_ONLN);
+		players_per_team = get_numcpus();
 
 	tst_atomic_store(0, &players_ready);
 
-- 
2.47.1


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Re: [LTP] [PATCH] sched_football: isolcpus handling

[Petr Vorel]

Hi Attila,

> sched_football expects each player thread is scheduleable
> to all of the physical CPU threads, however for example
> when you are using isolcpus by default you threads are
> not scheduled to some CPU. It leads to the test hangs.
> 591c56b045b2d44a0f4ba1a13545420b23e909b5solved was asimilar issue
nit: missing spaces:
591c56b045b2d44a0f4ba1a13545420b23e909b5 solved was a similar issue
> in realtime/prio-preempt .

> Signed-off-by: Attila Fazekas <afazekas@redhat.com>
> ---
>  .../realtime/func/sched_football/sched_football.c  | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)

> diff --git a/testcases/realtime/func/sched_football/sched_football.c b/testcases/realtime/func/sched_football/sched_football.c
> index 763b41f23..e4ae6a027 100644
> --- a/testcases/realtime/func/sched_football/sched_football.c
> +++ b/testcases/realtime/func/sched_football/sched_football.c
> @@ -133,6 +133,18 @@ void referee(int game_length)
>  	TST_EXP_EXPR(final_ball == 0);
>  }

> +static inline int get_numcpus(void)
> +{
> +	cpu_set_t mask;
> +
> +	CPU_ZERO(&mask);
> +
> +	/* Get the number of cpus accessible to the current process */
> +	sched_getaffinity(getpid(), sizeof(mask), &mask);
> +
> +	return CPU_COUNT(&mask);
> +}

Can't we unify these get_numcpus() functions and move to librttest.[ch]?

Also we have similar code in testcases/kernel/sched/cfs-scheduler/starvation.c
added in 1800e635783b69cacdce9f654ecd730a8f30915b (uses code from
lib/tst_cpu.c), but that's outside of testcases/realtime/, thus let's keep it
untouched.

Kind regards,
Petr

> +
>  static void do_test(void)
>  {
>  	struct sched_param param;
> @@ -140,7 +152,7 @@ static void do_test(void)
>  	int i;

>  	if (players_per_team == 0)
> -		players_per_team = sysconf(_SC_NPROCESSORS_ONLN);
> +		players_per_team = get_numcpus();

>  	tst_atomic_store(0, &players_ready);

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