Re: [PATCH #upstream-fixes] sata_sil24: configure max read request size to 4k

[Jeff Garzik <jeff@garzik.org>]

Tejun Heo wrote:
> Due to request posting limitations, bandwidth of sil3132 is limited to
> around 120MB/s with the minimum pci-e payload size (128bytes) which is
> used by most consumer systems.  However, write throughput can be
> slightly (~3%) increased by increasing the max read requeset size.
> Configure it to 4k which is the maximum supported.  This optimization
> is also done by SIMG's windows driver.
> 
> Signed-off-by: Tejun Heo <tj@kernel.org>
> ---
>  drivers/ata/sata_sil24.c |    5 +++++
>  1 file changed, 5 insertions(+)
> diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c
> index 4621807..ccee930 100644
> --- a/drivers/ata/sata_sil24.c
> +++ b/drivers/ata/sata_sil24.c
> @@ -1329,6 +1329,11 @@ static int sil24_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
>  		}
>  	}
>  
> +	/* Set max read request size to 4096.  This slightly increases
> +	 * write throughput for pci-e variants.
> +	 */
> +	pcie_set_readrq(pdev, 4096);
> +
>  	sil24_init_controller(host);
>  

applied