From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from emh02.mail.saunalahti.fi ([62.142.5.108]:60804 "EHLO emh02.mail.saunalahti.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751273Ab0HBNza convert rfc822-to-8bit (ORCPT ); Mon, 2 Aug 2010 09:55:30 -0400 Message-ID: <4C56CE4D.2060206@kolumbus.fi> Date: Mon, 02 Aug 2010 16:55:25 +0300 From: Marko Ristola MIME-Version: 1.0 To: VDR User CC: Emmanuel , linux-media@vger.kernel.org Subject: Re: [Q]: any DVB-S2 card which is 45MS/s capable? References: <4C4C475E.5060500@gmail.com> <4C4DDB83.9040009@gmail.com> <4C4ED694.5010505@gmail.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8BIT Sender: linux-media-owner@vger.kernel.org List-ID: Hi. I have written some Mantis bandwidth related DMA transfer optimizations on June/July this year. They are now waiting for approval by Manu Abraham. Those reduce CPU pressure, increasing the bandwidth that can be received from the DVB card. 45MS/s bandwidth support will surely benefit from those patches. Main features: 1. Do one CPU interrupt per 16KB data instead per 4KB data. My implementation benefits only Mantis cards. https://patchwork.kernel.org/patch/107036/ 2. Remove unnecessary big CPU overhead, when data is delivered from the DVB card's DMA buffer into Linux kernel's DVB subsystem. Number 2 reduces the CPU pressure by almost 50%. This implementation benefits many other Linux supported DVB cards too. http://patchwork.kernel.org/patch/108274/ Those helped with my older single CPU Core computer with 256-QAM, delivering HDTV channel into the network and watching the HDTV channel with a faster computer. The performance bottlenecks could be seen on the command line with "perf top". I had to increase PCI bus latency setting into 64 too from the BIOS. Moving DVB device into separate IRQ line with Ethernet card helped too, because Ethernet card did an interrupt per ethernet packet. So if the hardware can deliver 45MS/s data fast enough, software side can be optimized up to some point. My patches contain the most easy major optimizations that I found. If you can test some of those patches, it might help to get them into Linux kernel faster. Best regards, Marko Ristola 27.07.2010 18:11, VDR User wrote: > On Tue, Jul 27, 2010 at 5:52 AM, Emmanuel wrote: >> VDR User a écrit : >>> Look at the vp-1041 I think. >> From what I gathered it is not able to do 45MS/s for DVB-S2. >> Thanks anyway, > You may want to ask Manu Abraham (author of the mantis driver) about > that to be sure. It seems I recall him telling me it could quite some > time ago. > -- > To unsubscribe from this list: send the line "unsubscribe linux-media" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >