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

From: Pavel Machek
Date: Mon Dec 05 2005 - 16:21:53 EST


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@xxxxxxxxxx>
>
> ---
>
> 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!
-
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