On Mon, Nov 14, 2016 at 08:57:11AM -0800, Paul E. McKenney wrote: > Although rcutorture will occasionally do a 50-millisecond grace-period > delay, these delays are quite rare. And rightly so, because otherwise > the read rate would be quite low. Thie means that it can be important > to identify whether or not a given run contained a long-delay read. > This commit therefore inserts a trace_rcu_torture_read() event to flag > runs containing long delays. > > Signed-off-by: Paul E. McKenney <[email protected]>
A couple of apparent typos below. With those fixed: Reviewed-by: Josh Triplett <[email protected]> > include/trace/events/rcu.h | 5 ++++- > kernel/rcu/rcutorture.c | 11 ++++++++++- > 2 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h > index d3e756539d44..b31e05bc8e26 100644 > --- a/include/trace/events/rcu.h > +++ b/include/trace/events/rcu.h > @@ -698,7 +698,10 @@ TRACE_EVENT(rcu_batch_end, > /* > * Tracepoint for rcutorture readers. The first argument is the name > * of the RCU flavor from rcutorture's viewpoint and the second argument > - * is the callback address. > + * is the callback address. The third callback is the start time in > + * seconds, and the last two arguments are the grace period numbers > + * and the beginning and end of the read, respectively. Note that the > + * callback address can be NULL. s/third callback/third argument/? Also, s/and the beginning/of the beginning/? > TRACE_EVENT(rcu_torture_read, > > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c > index bf08fee53dc7..87c51225ceec 100644 > --- a/kernel/rcu/rcutorture.c > +++ b/kernel/rcu/rcutorture.c > @@ -289,15 +289,24 @@ static int rcu_torture_read_lock(void) __acquires(RCU) > > static void rcu_read_delay(struct torture_random_state *rrsp) > { > + unsigned long started; > + unsigned long completed; > const unsigned long shortdelay_us = 200; > const unsigned long longdelay_ms = 50; > + unsigned long long ts; > > /* We want a short delay sometimes to make a reader delay the grace > * period, and we want a long delay occasionally to trigger > * force_quiescent_state. */ > > - if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) > + if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) { > + started = cur_ops->completed(); > + ts = rcu_trace_clock_local(); > mdelay(longdelay_ms); > + completed = cur_ops->completed(); > + do_trace_rcu_torture_read(cur_ops->name, NULL, ts, > + started, completed); > + } > if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) > udelay(shortdelay_us); > #ifdef CONFIG_PREEMPT > -- > 2.5.2 >
