From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH #upstream-fixes] sata_sil24: configure max read request size to 4k Date: Sat, 25 Oct 2008 14:26:54 +0900 Message-ID: <4902AE1E.5020504@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from hera.kernel.org ([140.211.167.34]:57673 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750846AbYJYF1I (ORCPT ); Sat, 25 Oct 2008 01:27:08 -0400 Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Pierre Ossman , Jeff Garzik , IDE/ATA development list 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 --- 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); pci_set_master(pdev);