Re: [dpdk-stable] [PATCH] test/service: fix wait for service core

Re: [dpdk-stable] [PATCH] test/service: fix wait for service core

[Van Haaren, Harry]

> -----Original Message-----
> From: Aaron Conole <aconole@redhat.com>
> Sent: Wednesday, November 27, 2019 2:10 PM
> To: Van Haaren, Harry <harry.van.haaren@intel.com>
> Cc: dev@dpdk.org
> Subject: Re: [PATCH] test/service: fix wait for service core
> 
> Harry van Haaren <harry.van.haaren@intel.com> writes:
> 
> > This commit fixes a sporadic failure of the service_autotest
> > unit test, as seen in the DPDK CI. The failure occurs as the main test
> > thread did not wait on the service-thread to return, and allowing it
> > to read a flag before the service was able to write to it.
> >
> > The fix changes the wait API call to specific the service-core ID,
> > and this waits for cores with both ROLE_RTE and ROLE_SERVICE.
> >
> > The rte_eal_mp_wait_lcore() call does not (and should not) wait
> > for service cores, so must not be used to wait on service-cores.
> >
> > Fixes: f038a81e1c56 ("service: add unit tests")
> >
> > Reported-by: Aaron Conole <aconole@redhat.com>
> > Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
> >
> > ---
> 
> It might also be good to document this behavior in the API area.  It's
> unclear that the lcore wait function which takes a core id will work,
> but the broad wait will not.

Yes agreed that docs can improve here - different patch.


> > Given this is a fix in the unit test, and not a functional change
> > I'm not sure its worth backporting to LTS / stable releases?
> > I've not added stable on CC yet.
> 
> I think it's worth it if the LTS / stable branches use the unit tests
> (otherwise, they will observe sporadic failures).

Ok, I've added stable@dpdk.org on CC now


> >  app/test/test_service_cores.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/app/test/test_service_cores.c b/app/test/test_service_cores.c
> > index 9fe38f5e0..a922c7ddc 100644
> > --- a/app/test/test_service_cores.c
> > +++ b/app/test/test_service_cores.c
> > @@ -483,7 +483,7 @@ service_lcore_en_dis_able(void)
> >  	int ret = rte_eal_remote_launch(service_remote_launch_func, NULL,
> >  					slcore_id);
> >  	TEST_ASSERT_EQUAL(0, ret, "Ex-service core remote launch failed.");
> > -	rte_eal_mp_wait_lcore();
> > +	rte_eal_wait_lcore(slcore_id);
> >  	TEST_ASSERT_EQUAL(1, service_remote_launch_flag,
> >  			"Ex-service core function call had no effect.");
> 
> Should we also have some change like the following (just a guess):
> 
> diff --git a/app/test/test_service_cores.c b/app/test/test_service_cores.c
> index 9fe38f5e08..695c35ac6c 100644
> --- a/app/test/test_service_cores.c
> +++ b/app/test/test_service_cores.c
> @@ -773,7 +773,7 @@ service_app_lcore_poll_impl(const int mt_safe)
> 
>  	/* flag done, then wait for the spawned 2nd core to return */
>  	params[0] = 1;
> -	rte_eal_mp_wait_lcore();
> +	rte_eal_wait_lcore(app_core2);
> 
>  	/* core two gets launched first - and should hold the service lock */
>  	TEST_ASSERT_EQUAL(0, app_core2_ret,


I reviewed this usage of the function, and I believe it waits on application
cores (aka, ROLE_RTE, not ROLE_SERVICE). Hence this usage is actually correct.
Please review and double check my logic though - more eyes is good.

Re: [dpdk-stable] [PATCH] test/service: fix wait for service core

[David Marchand]

On Wed, Nov 27, 2019 at 3:16 PM Van Haaren, Harry
<harry.van.haaren@intel.com> wrote:
>
> > -----Original Message-----
> > From: Aaron Conole <aconole@redhat.com>
> > Sent: Wednesday, November 27, 2019 2:10 PM
> > To: Van Haaren, Harry <harry.van.haaren@intel.com>
> > Cc: dev@dpdk.org
> > Subject: Re: [PATCH] test/service: fix wait for service core
> >
> > Harry van Haaren <harry.van.haaren@intel.com> writes:
> >
> > > This commit fixes a sporadic failure of the service_autotest
> > > unit test, as seen in the DPDK CI. The failure occurs as the main test
> > > thread did not wait on the service-thread to return, and allowing it
> > > to read a flag before the service was able to write to it.
> > >
> > > The fix changes the wait API call to specific the service-core ID,
> > > and this waits for cores with both ROLE_RTE and ROLE_SERVICE.
> > >
> > > The rte_eal_mp_wait_lcore() call does not (and should not) wait
> > > for service cores, so must not be used to wait on service-cores.
> > >
> > > Fixes: f038a81e1c56 ("service: add unit tests")
> > >
> > > Reported-by: Aaron Conole <aconole@redhat.com>
> > > Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
> > >
> > > ---
> >
> > It might also be good to document this behavior in the API area.  It's
> > unclear that the lcore wait function which takes a core id will work,
> > but the broad wait will not.
>
> Yes agreed that docs can improve here - different patch.
>
>
> > > Given this is a fix in the unit test, and not a functional change
> > > I'm not sure its worth backporting to LTS / stable releases?
> > > I've not added stable on CC yet.
> >
> > I think it's worth it if the LTS / stable branches use the unit tests
> > (otherwise, they will observe sporadic failures).
>
> Ok, I've added stable@dpdk.org on CC now
>
>
> > >  app/test/test_service_cores.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/app/test/test_service_cores.c b/app/test/test_service_cores.c
> > > index 9fe38f5e0..a922c7ddc 100644
> > > --- a/app/test/test_service_cores.c
> > > +++ b/app/test/test_service_cores.c
> > > @@ -483,7 +483,7 @@ service_lcore_en_dis_able(void)
> > >     int ret = rte_eal_remote_launch(service_remote_launch_func, NULL,
> > >                                     slcore_id);
> > >     TEST_ASSERT_EQUAL(0, ret, "Ex-service core remote launch failed.");
> > > -   rte_eal_mp_wait_lcore();
> > > +   rte_eal_wait_lcore(slcore_id);
> > >     TEST_ASSERT_EQUAL(1, service_remote_launch_flag,
> > >                     "Ex-service core function call had no effect.");
> >
> > Should we also have some change like the following (just a guess):
> >
> > diff --git a/app/test/test_service_cores.c b/app/test/test_service_cores.c
> > index 9fe38f5e08..695c35ac6c 100644
> > --- a/app/test/test_service_cores.c
> > +++ b/app/test/test_service_cores.c
> > @@ -773,7 +773,7 @@ service_app_lcore_poll_impl(const int mt_safe)
> >
> >       /* flag done, then wait for the spawned 2nd core to return */
> >       params[0] = 1;
> > -     rte_eal_mp_wait_lcore();
> > +     rte_eal_wait_lcore(app_core2);
> >
> >       /* core two gets launched first - and should hold the service lock */
> >       TEST_ASSERT_EQUAL(0, app_core2_ret,
>
>
> I reviewed this usage of the function, and I believe it waits on application
> cores (aka, ROLE_RTE, not ROLE_SERVICE). Hence this usage is actually correct.
> Please review and double check my logic though - more eyes is good.
>

I will check it later tonight but I am for taking this in 19.11 if we
can get more stable tests.
Aaron, do you have an objection?


-- 
David Marchand

Re: [dpdk-stable] [PATCH] test/service: fix wait for service core

[Aaron Conole]

David Marchand <david.marchand@redhat.com> writes:

> On Wed, Nov 27, 2019 at 3:16 PM Van Haaren, Harry
> <harry.van.haaren@intel.com> wrote:
>>
>> > -----Original Message-----
>> > From: Aaron Conole <aconole@redhat.com>
>> > Sent: Wednesday, November 27, 2019 2:10 PM
>> > To: Van Haaren, Harry <harry.van.haaren@intel.com>
>> > Cc: dev@dpdk.org
>> > Subject: Re: [PATCH] test/service: fix wait for service core
>> >
>> > Harry van Haaren <harry.van.haaren@intel.com> writes:
>> >
>> > > This commit fixes a sporadic failure of the service_autotest
>> > > unit test, as seen in the DPDK CI. The failure occurs as the main test
>> > > thread did not wait on the service-thread to return, and allowing it
>> > > to read a flag before the service was able to write to it.
>> > >
>> > > The fix changes the wait API call to specific the service-core ID,
>> > > and this waits for cores with both ROLE_RTE and ROLE_SERVICE.
>> > >
>> > > The rte_eal_mp_wait_lcore() call does not (and should not) wait
>> > > for service cores, so must not be used to wait on service-cores.
>> > >
>> > > Fixes: f038a81e1c56 ("service: add unit tests")
>> > >
>> > > Reported-by: Aaron Conole <aconole@redhat.com>
>> > > Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
>> > >
>> > > ---
>> >
>> > It might also be good to document this behavior in the API area.  It's
>> > unclear that the lcore wait function which takes a core id will work,
>> > but the broad wait will not.
>>
>> Yes agreed that docs can improve here - different patch.
>>
>>
>> > > Given this is a fix in the unit test, and not a functional change
>> > > I'm not sure its worth backporting to LTS / stable releases?
>> > > I've not added stable on CC yet.
>> >
>> > I think it's worth it if the LTS / stable branches use the unit tests
>> > (otherwise, they will observe sporadic failures).
>>
>> Ok, I've added stable@dpdk.org on CC now
>>
>>
>> > >  app/test/test_service_cores.c | 2 +-
>> > >  1 file changed, 1 insertion(+), 1 deletion(-)
>> > >
>> > > diff --git a/app/test/test_service_cores.c b/app/test/test_service_cores.c
>> > > index 9fe38f5e0..a922c7ddc 100644
>> > > --- a/app/test/test_service_cores.c
>> > > +++ b/app/test/test_service_cores.c
>> > > @@ -483,7 +483,7 @@ service_lcore_en_dis_able(void)
>> > >     int ret = rte_eal_remote_launch(service_remote_launch_func, NULL,
>> > >                                     slcore_id);
>> > >     TEST_ASSERT_EQUAL(0, ret, "Ex-service core remote launch failed.");
>> > > -   rte_eal_mp_wait_lcore();
>> > > +   rte_eal_wait_lcore(slcore_id);
>> > >     TEST_ASSERT_EQUAL(1, service_remote_launch_flag,
>> > >                     "Ex-service core function call had no effect.");
>> >
>> > Should we also have some change like the following (just a guess):
>> >
>> > diff --git a/app/test/test_service_cores.c b/app/test/test_service_cores.c
>> > index 9fe38f5e08..695c35ac6c 100644
>> > --- a/app/test/test_service_cores.c
>> > +++ b/app/test/test_service_cores.c
>> > @@ -773,7 +773,7 @@ service_app_lcore_poll_impl(const int mt_safe)
>> >
>> >       /* flag done, then wait for the spawned 2nd core to return */
>> >       params[0] = 1;
>> > -     rte_eal_mp_wait_lcore();
>> > +     rte_eal_wait_lcore(app_core2);
>> >
>> >       /* core two gets launched first - and should hold the service lock */
>> >       TEST_ASSERT_EQUAL(0, app_core2_ret,
>>
>>
>> I reviewed this usage of the function, and I believe it waits on application
>> cores (aka, ROLE_RTE, not ROLE_SERVICE). Hence this usage is actually correct.
>> Please review and double check my logic though - more eyes is good.
>>
>
> I will check it later tonight but I am for taking this in 19.11 if we
> can get more stable tests.
> Aaron, do you have an objection?

No objection

Re: [dpdk-stable] [PATCH] test/service: fix wait for service core

[David Marchand]

On Wed, Nov 27, 2019 at 3:16 PM Van Haaren, Harry
<harry.van.haaren@intel.com> wrote:
>
> > -----Original Message-----
> > From: Aaron Conole <aconole@redhat.com>
> > Sent: Wednesday, November 27, 2019 2:10 PM
> > To: Van Haaren, Harry <harry.van.haaren@intel.com>
> > Cc: dev@dpdk.org
> > Subject: Re: [PATCH] test/service: fix wait for service core
> >
> > Harry van Haaren <harry.van.haaren@intel.com> writes:
> >
> > > This commit fixes a sporadic failure of the service_autotest
> > > unit test, as seen in the DPDK CI. The failure occurs as the main test
> > > thread did not wait on the service-thread to return, and allowing it
> > > to read a flag before the service was able to write to it.
> > >
> > > The fix changes the wait API call to specific the service-core ID,
> > > and this waits for cores with both ROLE_RTE and ROLE_SERVICE.
> > >
> > > The rte_eal_mp_wait_lcore() call does not (and should not) wait
> > > for service cores, so must not be used to wait on service-cores.
> > >
> > > Fixes: f038a81e1c56 ("service: add unit tests")
> > >
> > > Reported-by: Aaron Conole <aconole@redhat.com>
> > > Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
> > >
> > > ---
> >
> > It might also be good to document this behavior in the API area.  It's
> > unclear that the lcore wait function which takes a core id will work,
> > but the broad wait will not.
>
> Yes agreed that docs can improve here - different patch.
>
>
> > > Given this is a fix in the unit test, and not a functional change
> > > I'm not sure its worth backporting to LTS / stable releases?
> > > I've not added stable on CC yet.
> >
> > I think it's worth it if the LTS / stable branches use the unit tests
> > (otherwise, they will observe sporadic failures).
>
> Ok, I've added stable@dpdk.org on CC now
>
>
> > >  app/test/test_service_cores.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/app/test/test_service_cores.c b/app/test/test_service_cores.c
> > > index 9fe38f5e0..a922c7ddc 100644
> > > --- a/app/test/test_service_cores.c
> > > +++ b/app/test/test_service_cores.c
> > > @@ -483,7 +483,7 @@ service_lcore_en_dis_able(void)
> > >     int ret = rte_eal_remote_launch(service_remote_launch_func, NULL,
> > >                                     slcore_id);
> > >     TEST_ASSERT_EQUAL(0, ret, "Ex-service core remote launch failed.");
> > > -   rte_eal_mp_wait_lcore();
> > > +   rte_eal_wait_lcore(slcore_id);
> > >     TEST_ASSERT_EQUAL(1, service_remote_launch_flag,
> > >                     "Ex-service core function call had no effect.");
> >
> > Should we also have some change like the following (just a guess):
> >
> > diff --git a/app/test/test_service_cores.c b/app/test/test_service_cores.c
> > index 9fe38f5e08..695c35ac6c 100644
> > --- a/app/test/test_service_cores.c
> > +++ b/app/test/test_service_cores.c
> > @@ -773,7 +773,7 @@ service_app_lcore_poll_impl(const int mt_safe)
> >
> >       /* flag done, then wait for the spawned 2nd core to return */
> >       params[0] = 1;
> > -     rte_eal_mp_wait_lcore();
> > +     rte_eal_wait_lcore(app_core2);
> >
> >       /* core two gets launched first - and should hold the service lock */
> >       TEST_ASSERT_EQUAL(0, app_core2_ret,
>
>
> I reviewed this usage of the function, and I believe it waits on application
> cores (aka, ROLE_RTE, not ROLE_SERVICE). Hence this usage is actually correct.
> Please review and double check my logic though - more eyes is good.

It seems to be the case, yes.
My overall feeling is that the services stuff is a giant hack, so
better documentation will prove me wrong :-).

As I said I am for taking this change in 19.11 now, as it only impacts
this test and it seems to solve the random failures.

Acked-by: David Marchand <david.marchand@redhat.com>


-- 
David Marchand

Re: [dpdk-stable] [dpdk-dev] [PATCH] test/service: fix wait for service core

[David Marchand]

On Wed, Nov 27, 2019 at 2:20 PM Harry van Haaren
<harry.van.haaren@intel.com> wrote:
>
> This commit fixes a sporadic failure of the service_autotest
> unit test, as seen in the DPDK CI. The failure occurs as the main test
> thread did not wait on the service-thread to return, and allowing it
> to read a flag before the service was able to write to it.
>
> The fix changes the wait API call to specific the service-core ID,
> and this waits for cores with both ROLE_RTE and ROLE_SERVICE.
>
> The rte_eal_mp_wait_lcore() call does not (and should not) wait
> for service cores, so must not be used to wait on service-cores.
>
> Fixes: f038a81e1c56 ("service: add unit tests")
Cc: stable@dpdk.org

>
> Reported-by: Aaron Conole <aconole@redhat.com>
> Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>

Acked-by: David Marchand <david.marchand@redhat.com>

Before this patch, reproduced the pb in less than 2 minutes with:
# time (log=/tmp/$$.log; while true; do echo service_autotest |taskset
-c 0-1 build-gcc-static/app/test/dpdk-test --log-level *:8 -l 0-1
>$log 2>&1; grep -q 'Test OK' $log || break; done; cat $log; rm -f
$log)

With the patch, this loop has been running for 40 minutes.

Applied, thanks.


--
David Marchand