[v3,2/2] test/service: fix race condition on stopping lcore

  This commit fixes a potential race condition in the tests
where the lcore running a service would increment a counter
that was already reset by the test-suite thread. The resulting
race-condition incremented value could cause CI failures, as
indicated by DPDK's CI.

This patch fixes the race-condition by making use of the
added rte_service_lcore_active() API, which indicates when
a service-core is no longer in the service-core polling loop.

The unit test makes use of the above function to detect when
all statistics increments are done in the service-core thread,
and then the unit test continues finalizing and checking state.

Fixes: f28f3594ded2 ("service: add attribute API")

Reported-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Reviewed-by: Phil Yang <phil.yang@arm.com>

---

v3:
- Refactor while() to for() to simplify (Harry)
- Use SERVICE_DELAY instead of magic const 1 (Phil)
- Add Phil's reviewed by tag from ML

v2:
Thanks for discussion on v1, this v2 fixup for the CI
including previous feedback on ML.
---
 app/test/test_service_cores.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)
  

<snip>

> Subject: [PATCH v3 2/2] test/service: fix race condition on stopping lcore
> 
> This commit fixes a potential race condition in the tests where the lcore
> running a service would increment a counter that was already reset by the
> test-suite thread. The resulting race-condition incremented value could cause
> CI failures, as indicated by DPDK's CI.
> 
> This patch fixes the race-condition by making use of the added
> rte_service_lcore_active() API, which indicates when a service-core is no
> longer in the service-core polling loop.
> 
> The unit test makes use of the above function to detect when all statistics
> increments are done in the service-core thread, and then the unit test
> continues finalizing and checking state.
> 
> Fixes: f28f3594ded2 ("service: add attribute API")
> 
> Reported-by: David Marchand <david.marchand@redhat.com>
> Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
> Reviewed-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

> 
> ---
> 
> v3:
> - Refactor while() to for() to simplify (Harry)
> - Use SERVICE_DELAY instead of magic const 1 (Phil)
> - Add Phil's reviewed by tag from ML
> 
> v2:
> Thanks for discussion on v1, this v2 fixup for the CI including previous
> feedback on ML.
> ---
>  app/test/test_service_cores.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/app/test/test_service_cores.c b/app/test/test_service_cores.c index
> ef1d8fcb9..a6bc4487e 100644
> --- a/app/test/test_service_cores.c
> +++ b/app/test/test_service_cores.c
> @@ -362,6 +362,9 @@ service_lcore_attr_get(void)
>  			"Service core add did not return zero");
>  	TEST_ASSERT_EQUAL(0, rte_service_map_lcore_set(id, slcore_id, 1),
>  			"Enabling valid service and core failed");
> +	/* Ensure service is not active before starting */
> +	TEST_ASSERT_EQUAL(0, rte_service_lcore_active(slcore_id),
> +			"Not-active service core reported as active");
>  	TEST_ASSERT_EQUAL(0, rte_service_lcore_start(slcore_id),
>  			"Starting service core failed");
> 
> @@ -382,7 +385,22 @@ service_lcore_attr_get(void)
>  			lcore_attr_id, &lcore_attr_value),
>  			"Invalid lcore attr didn't return -EINVAL");
> 
> -	rte_service_lcore_stop(slcore_id);
> +	/* Ensure service is active */
> +	TEST_ASSERT_EQUAL(1, rte_service_lcore_active(slcore_id),
> +			"Active service core reported as not-active");
> +
> +	TEST_ASSERT_EQUAL(0, rte_service_map_lcore_set(id, slcore_id, 0),
> +			"Disabling valid service and core failed");
> +	TEST_ASSERT_EQUAL(0, rte_service_lcore_stop(slcore_id),
> +			"Failed to stop service lcore");
> +
> +	/* Wait until service lcore not active, or for 100x SERVICE_DELAY */
> +	for (int i = 0; i < 100 && rte_service_lcore_active(slcore_id) == 1;
> +			i++)
> +		rte_delay_ms(SERVICE_DELAY);
> +
> +	TEST_ASSERT_EQUAL(0, rte_service_lcore_active(slcore_id),
> +			  "Service lcore not stopped after waiting.");
> 
>  	TEST_ASSERT_EQUAL(0, rte_service_lcore_attr_reset_all(slcore_id),
>  			  "Valid lcore_attr_reset_all() didn't return success");
> --
> 2.17.1