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authorPaul E. McKenney <paulmck@kernel.org>2020-11-15 21:24:52 +0300
committerPaul E. McKenney <paulmck@kernel.org>2021-01-07 04:08:09 +0300
commite76506f0e85129d726c487c873a2245c92446515 (patch)
treed0faf8f967b063a9b29e7f66b65f5118b20118be /kernel/rcu
parentf3ea978b712f768a02137e867aced5bfdcea670e (diff)
downloadlinux-e76506f0e85129d726c487c873a2245c92446515.tar.xz
refscale: Allow summarization of verbose output
The refscale test prints enough per-kthread console output to provoke RCU CPU stall warnings on large systems. This commit therefore allows this output to be summarized. For example, the refscale.verbose_batched=32 boot parameter would causes only every 32nd line of output to be logged. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/refscale.c21
1 files changed, 16 insertions, 5 deletions
diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c
index 23ff36a66f97..3da246f2ccf5 100644
--- a/kernel/rcu/refscale.c
+++ b/kernel/rcu/refscale.c
@@ -46,6 +46,16 @@
#define VERBOSE_SCALEOUT(s, x...) \
do { if (verbose) pr_alert("%s" SCALE_FLAG s, scale_type, ## x); } while (0)
+static atomic_t verbose_batch_ctr;
+
+#define VERBOSE_SCALEOUT_BATCH(s, x...) \
+do { \
+ if (verbose && \
+ (verbose_batched <= 0 || \
+ !(atomic_inc_return(&verbose_batch_ctr) % verbose_batched))) \
+ pr_alert("%s" SCALE_FLAG s, scale_type, ## x); \
+} while (0)
+
#define VERBOSE_SCALEOUT_ERRSTRING(s, x...) \
do { if (verbose) pr_alert("%s" SCALE_FLAG "!!! " s, scale_type, ## x); } while (0)
@@ -57,6 +67,7 @@ module_param(scale_type, charp, 0444);
MODULE_PARM_DESC(scale_type, "Type of test (rcu, srcu, refcnt, rwsem, rwlock.");
torture_param(int, verbose, 0, "Enable verbose debugging printk()s");
+torture_param(int, verbose_batched, 0, "Batch verbose debugging printk()s");
// Wait until there are multiple CPUs before starting test.
torture_param(int, holdoff, IS_BUILTIN(CONFIG_RCU_REF_SCALE_TEST) ? 10 : 0,
@@ -368,14 +379,14 @@ ref_scale_reader(void *arg)
u64 start;
s64 duration;
- VERBOSE_SCALEOUT("ref_scale_reader %ld: task started", me);
+ VERBOSE_SCALEOUT_BATCH("ref_scale_reader %ld: task started", me);
set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
set_user_nice(current, MAX_NICE);
atomic_inc(&n_init);
if (holdoff)
schedule_timeout_interruptible(holdoff * HZ);
repeat:
- VERBOSE_SCALEOUT("ref_scale_reader %ld: waiting to start next experiment on cpu %d", me, smp_processor_id());
+ VERBOSE_SCALEOUT_BATCH("ref_scale_reader %ld: waiting to start next experiment on cpu %d", me, smp_processor_id());
// Wait for signal that this reader can start.
wait_event(rt->wq, (atomic_read(&nreaders_exp) && smp_load_acquire(&rt->start_reader)) ||
@@ -392,7 +403,7 @@ repeat:
while (atomic_read_acquire(&n_started))
cpu_relax();
- VERBOSE_SCALEOUT("ref_scale_reader %ld: experiment %d started", me, exp_idx);
+ VERBOSE_SCALEOUT_BATCH("ref_scale_reader %ld: experiment %d started", me, exp_idx);
// To reduce noise, do an initial cache-warming invocation, check
@@ -421,8 +432,8 @@ repeat:
if (atomic_dec_and_test(&nreaders_exp))
wake_up(&main_wq);
- VERBOSE_SCALEOUT("ref_scale_reader %ld: experiment %d ended, (readers remaining=%d)",
- me, exp_idx, atomic_read(&nreaders_exp));
+ VERBOSE_SCALEOUT_BATCH("ref_scale_reader %ld: experiment %d ended, (readers remaining=%d)",
+ me, exp_idx, atomic_read(&nreaders_exp));
if (!torture_must_stop())
goto repeat;