Re: [PATCH v3 1/3] rcutorture: Allow a negative value for nfakewriters

Uladzislau Rezki
2025-02-26T14:29:15Z

On Tue, Feb 25, 2025 at 04:24:09PM -0500, Joel Fernandes wrote:
> On Tue, Feb 25, 2025 at 12:00:18PM +0100, Uladzislau Rezki (Sony) wrote:
> > Currently "nfakewriters" parameter can be set to any value but
> > there is no possibility to adjust it automatically based on how
> > many CPUs a system has where a test is run on.
> >
> > To address this, if the "nfakewriters" is set to negative it will
> > be adjusted to num_online_cpus() during torture initialization.
> >
> > Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
> > Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> > ---
> > kernel/rcu/rcutorture.c | 22 ++++++++++++++++------
> > 1 file changed, 16 insertions(+), 6 deletions(-)
> >
> > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> > index d98b3bd6d91f..f376262532ce 100644
> > --- a/kernel/rcu/rcutorture.c
> > +++ b/kernel/rcu/rcutorture.c
> > @@ -148,6 +148,7 @@ MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
>
> IMO, this should also be updated to reflect the possibily to set it negative
> and hence to number CPUs:
>
> torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
>
You can set it to a negative as well as to number of CPUs or any other
number.

--
Uladzislau Rezki