Re: [RFC PATCH v2 17/20] rcutorture: Add a test config to torture test low RCU_DYNTICKS width

Valentin Schneider
2023-07-21T15:09:44Z

On 21/07/23 07:07, Paul E. McKenney wrote:
> On Fri, Jul 21, 2023 at 08:58:53AM +0100, Valentin Schneider wrote:
>> On 20/07/23 21:00, Paul E. McKenney wrote:
>> > On Thu, Jul 20, 2023 at 12:53:05PM -0700, Paul E. McKenney wrote:
>> >> On Thu, Jul 20, 2023 at 05:30:53PM +0100, Valentin Schneider wrote:
>> >> > diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE11 b/tools/testing/selftests/rcutorture/configs/rcu/TREE11
>> >> > new file mode 100644
>> >> > index 0000000000000..aa7274efd9819
>> >> > --- /dev/null
>> >> > +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE11
>> >> > @@ -0,0 +1,19 @@
>> >> > +CONFIG_SMP=y
>> >> > +CONFIG_NR_CPUS=8
>> >> > +CONFIG_PREEMPT_NONE=n
>> >> > +CONFIG_PREEMPT_VOLUNTARY=y
>> >> > +CONFIG_PREEMPT=n
>> >> > +CONFIG_PREEMPT_DYNAMIC=n
>> >> > +#CHECK#CONFIG_TREE_RCU=y
>> >> > +CONFIG_HZ_PERIODIC=n
>> >> > +CONFIG_NO_HZ_IDLE=n
>> >> > +CONFIG_NO_HZ_FULL=y
>> >> > +CONFIG_RCU_TRACE=y
>> >> > +CONFIG_RCU_FANOUT=4
>> >> > +CONFIG_RCU_FANOUT_LEAF=3
>> >> > +CONFIG_DEBUG_LOCK_ALLOC=n
>> >> > +CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
>> >> > +CONFIG_RCU_EXPERT=y
>> >> > +CONFIG_RCU_EQS_DEBUG=y
>> >> > +CONFIG_RCU_LAZY=y
>> >> > +CONFIG_RCU_DYNTICKS_BITS=2
>> >>
>> >> Why not just add this last line to the existing TREE04 scenario?
>> >> That would ensure that it gets tested regularly without extending the
>> >> time required to run a full set of rcutorture tests.
>> >
>> > Please see below for the version of this patch that I am running overnight
>> > tests with. Does this one work for you?
>>
>> Yep that's fine with me. I only went with a separate test file as wasn't
>> sure how new test options should be handled (merged into existing tests vs
>> new tests created), and didn't want to negatively impact TREE04 or
>> TREE06. If merging into TREE04 is preferred, then I'll do just that and
>> carry this path moving forwards.
>
> Things worked fine for this one-hour-per-scenario test run on my laptop,

Many thanks for testing!

> except for the CONFIG_SMP=n runs, which all got build errors like the
> following.
>

Harumph, yes !SMP (and !CONTEXT_TRACKING_WORK) doesn't compile nicely, I'll
fix that for v3.