Subject: Re: [PATCH bpf-next 13/15] selftests/xsk: merge dual and single thread dispatchers

From: Maciej Fijalkowski <[email-masked]>
Date: Mon, 12 Dec 2022 17:10:54 +0100

On Tue, Dec 06, 2022 at 10:08:24AM +0100, Magnus Karlsson wrote:
> From: Magnus Karlsson <[email-masked]>
> 
> Make the thread dispatching code common by unifying the dual and
> single thread dispatcher code. This so we do not have to add code in
> two places in upcoming commits.
> 
> Signed-off-by: Magnus Karlsson <[email-masked]>
> ---
>  tools/testing/selftests/bpf/xskxceiver.c | 120 ++++++++++-------------
>  1 file changed, 54 insertions(+), 66 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/xskxceiver.c b/tools/testing/selftests/bpf/xskxceiver.c
> index 522dc1d69c17..0457874c0995 100644
> --- a/tools/testing/selftests/bpf/xskxceiver.c
> +++ b/tools/testing/selftests/bpf/xskxceiver.c
> @@ -1364,85 +1364,61 @@ static void handler(int signum)
>  	pthread_exit(NULL);
>  }
>  
> -static int testapp_validate_traffic_single_thread(struct test_spec *test, struct ifobject *ifobj,
> -						  enum test_type type)
> +static int __testapp_validate_traffic(struct test_spec *test, struct ifobject *ifobj_rx,
> +				      struct ifobject *ifobj_tx)
>  {
> -	bool old_shared_umem = ifobj->shared_umem;
> -	pthread_t t0;
> -
> -	if (pthread_barrier_init(&barr, NULL, 2))
> -		exit_with_error(errno);
> -
> -	test->current_step++;
> -	if (type == TEST_TYPE_POLL_RXQ_TMOUT)
> -		pkt_stream_reset(ifobj->pkt_stream);
> -	pkts_in_flight = 0;
> -
> -	test->ifobj_rx->shared_umem = false;
> -	test->ifobj_tx->shared_umem = false;
> -
> -	signal(SIGUSR1, handler);
> -	/* Spawn thread */
> -	pthread_create(&t0, NULL, ifobj->func_ptr, test);
> -
> -	if (type != TEST_TYPE_POLL_TXQ_TMOUT)
> -		pthread_barrier_wait(&barr);
> -
> -	if (pthread_barrier_destroy(&barr))
> -		exit_with_error(errno);
> -
> -	pthread_kill(t0, SIGUSR1);
> -	pthread_join(t0, NULL);
> -
> -	if (test->total_steps == test->current_step || test->fail) {
> -		xsk_socket__delete(ifobj->xsk->xsk);
> -		xsk_clear_xskmap(ifobj->xskmap);
> -		testapp_clean_xsk_umem(ifobj);
> -	}
> -
> -	test->ifobj_rx->shared_umem = old_shared_umem;
> -	test->ifobj_tx->shared_umem = old_shared_umem;
> -
> -	return !!test->fail;
> -}
> -
> -static int testapp_validate_traffic(struct test_spec *test)
> -{
> -	struct ifobject *ifobj_tx = test->ifobj_tx;
> -	struct ifobject *ifobj_rx = test->ifobj_rx;
>  	pthread_t t0, t1;
>  
> -	if (pthread_barrier_init(&barr, NULL, 2))
> -		exit_with_error(errno);
> +	if (ifobj_tx)
> +		if (pthread_barrier_init(&barr, NULL, 2))
> +			exit_with_error(errno);
>  
>  	test->current_step++;
>  	pkt_stream_reset(ifobj_rx->pkt_stream);
>  	pkts_in_flight = 0;
>  
> +	signal(SIGUSR1, handler);
>  	/*Spawn RX thread */
>  	pthread_create(&t0, NULL, ifobj_rx->func_ptr, test);
>  
> -	pthread_barrier_wait(&barr);
> -	if (pthread_barrier_destroy(&barr))
> -		exit_with_error(errno);
> +	if (ifobj_tx) {
> +		pthread_barrier_wait(&barr);
> +		if (pthread_barrier_destroy(&barr))
> +			exit_with_error(errno);
>  
> -	/*Spawn TX thread */
> -	pthread_create(&t1, NULL, ifobj_tx->func_ptr, test);
> +		/*Spawn TX thread */
> +		pthread_create(&t1, NULL, ifobj_tx->func_ptr, test);
>  
> -	pthread_join(t1, NULL);
> -	pthread_join(t0, NULL);
> +		pthread_join(t1, NULL);
> +	}
> +
> +	if (!ifobj_tx)
> +		pthread_kill(t0, SIGUSR1);
> +	else
> +		pthread_join(t0, NULL);
>  
>  	if (test->total_steps == test->current_step || test->fail) {
> -		xsk_socket__delete(ifobj_tx->xsk->xsk);
> +		if (ifobj_tx)
> +			xsk_socket__delete(ifobj_tx->xsk->xsk);
>  		xsk_socket__delete(ifobj_rx->xsk->xsk);
>  		testapp_clean_xsk_umem(ifobj_rx);
> -		if (!ifobj_tx->shared_umem)
> +		if (ifobj_tx && !ifobj_tx->shared_umem)
>  			testapp_clean_xsk_umem(ifobj_tx);
>  	}
>  
>  	return !!test->fail;
>  }
>  
> +static int testapp_validate_traffic(struct test_spec *test)
> +{
> +	return __testapp_validate_traffic(test, test->ifobj_rx, test->ifobj_tx);
> +}
> +
> +static int testapp_validate_traffic_single_thread(struct test_spec *test, struct ifobject *ifobj)
> +{
> +	return __testapp_validate_traffic(test, ifobj, NULL);

One minor comment here is that for single thread we either spawn Rx or Tx
thread, whereas reading the code one could tell that single threaded test
works only on Rx.

Maybe rename to ifobj1 ifobj2 from ifobj_rx ifobj_rx? everything within is
generic, like, we have func_ptr, not tx_func_ptr, so this won't look odd
with ifobj1 as a name.

> +}
> +
>  static void testapp_teardown(struct test_spec *test)
>  {
>  	int i;
> @@ -1684,6 +1660,26 @@ static void testapp_xdp_drop(struct test_spec *test)
>  	ifobj->xskmap = ifobj->def_prog->maps.xsk;
>  }
>  
> +static void testapp_poll_txq_tmout(struct test_spec *test)
> +{
> +	test_spec_set_name(test, "POLL_TXQ_FULL");
> +
> +	test->ifobj_tx->use_poll = true;
> +	/* create invalid frame by set umem frame_size and pkt length equal to 2048 */
> +	test->ifobj_tx->umem->frame_size = 2048;
> +	pkt_stream_replace(test, 2 * DEFAULT_PKT_CNT, 2048);
> +	testapp_validate_traffic_single_thread(test, test->ifobj_tx);
> +
> +	pkt_stream_restore_default(test);
> +}
> +
> +static void testapp_poll_rxq_tmout(struct test_spec *test)
> +{
> +	test_spec_set_name(test, "POLL_RXQ_EMPTY");
> +	test->ifobj_rx->use_poll = true;
> +	testapp_validate_traffic_single_thread(test, test->ifobj_rx);
> +}
> +
>  static int xsk_load_xdp_programs(struct ifobject *ifobj)
>  {
>  	ifobj->def_prog = xsk_def_prog__open_and_load();
> @@ -1799,18 +1795,10 @@ static void run_pkt_test(struct test_spec *test, enum test_mode mode, enum test_
>  		testapp_validate_traffic(test);
>  		break;
>  	case TEST_TYPE_POLL_TXQ_TMOUT:
> -		test_spec_set_name(test, "POLL_TXQ_FULL");
> -		test->ifobj_tx->use_poll = true;
> -		/* create invalid frame by set umem frame_size and pkt length equal to 2048 */
> -		test->ifobj_tx->umem->frame_size = 2048;
> -		pkt_stream_replace(test, 2 * DEFAULT_PKT_CNT, 2048);
> -		testapp_validate_traffic_single_thread(test, test->ifobj_tx, type);
> -		pkt_stream_restore_default(test);
> +		testapp_poll_txq_tmout(test);
>  		break;
>  	case TEST_TYPE_POLL_RXQ_TMOUT:
> -		test_spec_set_name(test, "POLL_RXQ_EMPTY");
> -		test->ifobj_rx->use_poll = true;
> -		testapp_validate_traffic_single_thread(test, test->ifobj_rx, type);
> +		testapp_poll_rxq_tmout(test);
>  		break;
>  	case TEST_TYPE_ALIGNED_INV_DESC:
>  		test_spec_set_name(test, "ALIGNED_INV_DESC");
> -- 
> 2.34.1
>