Re: [PATCH] libertas: increase spi driver thread priority

[Dan Williams <dcbw@redhat.com>]

On Thu, 2009-04-02 at 14:44 -0700, Anna Neal wrote:
> Currently, the libertas main thread contends with the spi driver thread
> in the TX path.  To improve throughput, ensure that the driver thread
> has higher scheduling priority than the libertas main thread.  Do this
> by making the libertas spi driver thread a low priority real time
> thread.
> 
> We measured an average throughput improvement of 13%.
> 
> Signed-off-by: Anna Neal <anna@cozybit.com>
> Signed-off-by: Andrey Yurovsky <andrey@cozybit.com>

Sure; looks fine to me.  

Acked-by: Dan Williams <dcbw@redhat.com>

> ---
>  drivers/net/wireless/libertas/if_spi.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/net/wireless/libertas/if_spi.c b/drivers/net/wireless/libertas/if_spi.c
> index 07311e7..97493e2 100644
> --- a/drivers/net/wireless/libertas/if_spi.c
> +++ b/drivers/net/wireless/libertas/if_spi.c
> @@ -1020,6 +1020,7 @@ static int __devinit if_spi_probe(struct spi_device *spi)
>  	struct libertas_spi_platform_data *pdata = spi->dev.platform_data;
>  	int err = 0;
>  	u32 scratch;
> +	struct sched_param param = { .sched_priority = 1 };
>  
>  	lbs_deb_enter(LBS_DEB_SPI);
>  
> @@ -1123,6 +1124,9 @@ static int __devinit if_spi_probe(struct spi_device *spi)
>  		lbs_pr_err("error creating SPI thread: err=%d\n", err);
>  		goto remove_card;
>  	}
> +	if (sched_setscheduler(card->spi_thread, SCHED_FIFO, &param))
> +		lbs_pr_err("Error setting scheduler, using default.\n");
> +
>  	err = request_irq(spi->irq, if_spi_host_interrupt,
>  			IRQF_TRIGGER_FALLING, "libertas_spi", card);
>  	if (err) {