Re: [PATCH] Extend RCU torture module to test tickless idle CPU

[Pavel Machek <pavel@ucw.cz>]

Hi!

> This patch forces RCU torture threads off various CPUs in the system
> allowing them to become idle and go tickless.  Meant to test support for 
> such tickless idle CPU in RCU.
> 
> Signed-off-by : Srivatsa Vaddagiri <vatsa@in.ibm.com>
> 
> ---
> 
>  linux-2.6.15-rc5-mm1-root/kernel/rcutorture.c |   89 +++++++++++++++++++++++++-
>  1 files changed, 87 insertions(+), 2 deletions(-)
> 
> diff -puN kernel/rcutorture.c~rcutorture kernel/rcutorture.c
> --- linux-2.6.15-rc5-mm1/kernel/rcutorture.c~rcutorture	2005-12-05 15:33:34.000000000 +0530
> +++ linux-2.6.15-rc5-mm1-root/kernel/rcutorture.c	2005-12-05 15:33:42.000000000 +0530
> @@ -51,6 +51,8 @@ static int nreaders = -1;	/* # reader th
>  static int stat_interval = 0;	/* Interval between stats, in seconds. */
>  				/*  Defaults to "only at end of test". */
>  static int verbose = 0;		/* Print more debug info. */
> +static int test_no_idle_hz = 0; /* Test RCU's support for tickless idle CPUs. */

0 initializers are not needed. Also comment formatting is
"interesting".

> @@ -375,12 +382,77 @@ rcu_torture_stats(void *arg)
>  	return 0;
>  }
>  
> +int rcu_idle_cpu;	/* Force all torture tasks off this CPU */

Missing static?

> +/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
> + * system to become idle at a time and cut off its timer ticks. This is meant
> + * to test the support for such tickless idle CPU in RCU.
> + */
> +static int
> +rcu_torture_shuffle(void *arg)
> +{
> +	VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");

Do you really need to append _STRING here?

							Pavel
-- 
Thanks, Sharp!