From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: multiple irqs per card on the sata_sil24 Date: Wed, 27 Sep 2006 10:07:06 +0900 Message-ID: <4519CEBA.90307@gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from nz-out-0102.google.com ([64.233.162.202]:11331 "EHLO nz-out-0102.google.com") by vger.kernel.org with ESMTP id S932192AbWI0BHN (ORCPT ); Tue, 26 Sep 2006 21:07:13 -0400 Received: by nz-out-0102.google.com with SMTP id n1so5841nzf for ; Tue, 26 Sep 2006 18:07:12 -0700 (PDT) In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Trent George Cc: linux-ide@vger.kernel.org Trent George wrote: > While reading the specs, I noticed that the pci-x cards support splitting each port to a unique irq pin. 3124 doesn't seem to support multiple MSI interrupts either. Multiple Message Capable field is 000b. Where does the spec say that it can split each port to a unique irq pin? > If you have 6 cards with 4 ports, can you spread the load over 24 irqs ? > I dont know if the motherboard can support this, or the driver could be modified to do this. > It would be nice when there is a lot of of disk traffic on lots of drives.... adding port multiplier drives to each channel. > I am trying to build a VERY large duplication system using LOTS of bandwidth. the irq can really put stress on the system. Theoretically, yes, but linux currently cannot do multiple MSI interrupts and I don't think it's gonna be supported anytime soon. pci-e + multiple MSIX interrupts are supported but AFAIK 3132 supports that. sil24 is pretty efficient and it only takes one more register access to determine which port has raised interrupt. Also, if you have multiple busy ports w/ PMP attached, single interrupt is likely to serve multiple ports, so I don't think it's gonna matter performance-wise. > the final system would be 100+ drives all going over 22mb/s. > It should give a nice supermicro board with 3 buses a real workout. Impressive. Good luck and please keep us posted. -- tejun