From: Tejun Heo Date: Sat, 25 Oct 2008 05:26:54 +0000 (+0900) Subject: sata_sil24: configure max read request size to 4k X-Git-Tag: v2.6.28-rc3~93^2~5 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=e8b3b5e9f54512bfdb7c154da07ec0408cbd6c56;p=linux-2.6-omap-h63xx.git sata_sil24: configure max read request size to 4k 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 Signed-off-by: Jeff Garzik --- diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c index 4621807a1a6..ccee930f1e1 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); pci_set_master(pdev);