Messages in this thread | | | Date | Wed, 7 May 2014 16:56:33 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH tip/core/rcu 06/45] torture: Intensify locking test |
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On Wed, May 07, 2014 at 02:20:15PM -0700, josh@joshtriplett.org wrote: > On Mon, Apr 28, 2014 at 05:24:54PM -0700, Paul E. McKenney wrote: > > From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> > > > > The current lock_torture_writer() spends too much time sleeping and not > > enough time hammering locks, as in an eight-CPU test will often only be > > utilizing a CPU or two. This commit therefore makes lock_torture_writer() > > sleep less and hammer more. > > > > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > > --- > > kernel/locking/locktorture.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c > > index f26b1a18e34e..b0d3e3c50672 100644 > > --- a/kernel/locking/locktorture.c > > +++ b/kernel/locking/locktorture.c > > @@ -219,7 +219,8 @@ static int lock_torture_writer(void *arg) > > set_user_nice(current, 19); > > > > do { > > - schedule_timeout_uninterruptible(1); > > + if ((torture_random(&rand) & 0xfffff) == 0) > > + schedule_timeout_uninterruptible(1); > > That's a one-in-1048576 chance of sleeping for a jiffy; is that frequent > enough to even bother sleeping at all?
On large systems, maybe not. Smallish systems should be able to get through that loop a million times in a few hundreds of milliseconds, though. So longer term a smarter approach might be needed, but this should be a good start.
Thanx, Paul
> > cur_ops->writelock(); > > if (WARN_ON_ONCE(lock_is_write_held)) > > lwsp->n_write_lock_fail++; > > -- > > 1.8.1.5 > > >
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