From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH #upstream-fixes] sata_sil24: configure max read request size to 4k Date: Mon, 27 Oct 2008 23:58:02 -0400 Message-ID: <49068DCA.8010205@garzik.org> References: <4902AE1E.5020504@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:54375 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751372AbYJ1D6K (ORCPT ); Mon, 27 Oct 2008 23:58:10 -0400 In-Reply-To: <4902AE1E.5020504@kernel.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: Pierre Ossman , IDE/ATA development list 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 > --- > 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