Re: [PATCH v2 3/3] hw_random: increase schedule timeout in rng_dev_read()

Michael Büsch
2014-09-15T16:36:53Z

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On Tue, 16 Sep 2014 00:02:29 +0800
Amos Kong <akong@redhat.com> wrote:

> This patch increases the schedule timeout to 10 jiffies, it's more
> appropriate, then other takes can easy to hold the mutex lock.
>
> Signed-off-by: Amos Kong <akong@redhat.com>
> ---
> drivers/char/hw_random/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
> index 263a370..b5d1b6f 100644
> --- a/drivers/char/hw_random/core.c
> +++ b/drivers/char/hw_random/core.c
> @@ -195,7 +195,7 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
>
> mutex_unlock(&rng_mutex);
>
> - schedule_timeout_interruptible(1);
> + schedule_timeout_interruptible(10);
>
> if (signal_pending(current)) {
> err = -ERESTARTSYS;

Does a schedule of 1 ms or 10 ms decrease the throughput?
I think we need some benchmarks.

--
Michael

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