Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH tip/core/rcu 12/24] rcutorture: Avoid RCU CPU stall warning and RT throttling | Date | Tue, 12 Apr 2016 08:43:45 -0700 |
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Running rcuperf can result in RCU CPU stall warnings and RT throttling. These occur because on of the real-time writer processes does ftrace_dump() while still running at real-time priority. This commit therefore prevents these problems by setting the writer thread back to SCHED_NORMAL (AKA SCHED_OTHER) before doing ftrace_dump().
In addition, this commit adds a small fixed delay before dumping ftrace buffer in order to decrease the probability that this dumping will interfere with other writers' grace periods.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> --- kernel/rcu/rcuperf.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c index 278600143bb6..4c0572859ff0 100644 --- a/kernel/rcu/rcuperf.c +++ b/kernel/rcu/rcuperf.c @@ -404,11 +404,15 @@ rcu_perf_writer(void *arg) started = true; if (!done && i >= MIN_MEAS) { done = true; + sp.sched_priority = 0; + sched_setscheduler_nocheck(current, + SCHED_NORMAL, &sp); pr_alert("%s" PERF_FLAG "rcu_perf_writer %ld has %d measurements\n", perf_type, me, MIN_MEAS); if (atomic_inc_return(&n_rcu_perf_writer_finished) >= nrealwriters) { + schedule_timeout_interruptible(10); rcu_ftrace_dump(DUMP_ALL); PERFOUT_STRING("Test complete"); t_rcu_perf_writer_finished = t; -- 2.5.2
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