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

On 21/07/23 07:07, Paul E. McKenney wrote:

On Fri, Jul 21, 2023 at 08:58:53AM +0100, Valentin Schneider wrote:

quoted

On 20/07/23 21:00, Paul E. McKenney wrote:

quoted

On Thu, Jul 20, 2023 at 12:53:05PM -0700, Paul E. McKenney wrote:

quoted

On Thu, Jul 20, 2023 at 05:30:53PM +0100, Valentin Schneider wrote:

quoted

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.