From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([217.30.184.167]:39080 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751426AbZIENUM (ORCPT ); Sat, 5 Sep 2009 09:20:12 -0400 Message-ID: <4AA26587.7000506@iki.fi> Date: Sat, 05 Sep 2009 16:20:07 +0300 From: Antti Palosaari MIME-Version: 1.0 To: "linux-media@vger.kernel.org" , Heinrich Langos Subject: DVB USB stream parameters Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: What are preferred BULK stream parameters, .count and .buffersize? for USB2.0? for USB1.1? buffersize, which is URB size, have great effect to system load. For example 512 bytes generates about 10x more wakeups than 5120. It is quite clear that 512 is too small for whole DVB stream. I did some test and looks like all USB2.0 devices I have here allow x512 or x188 sizes. Heinrich Langos did some measurements and results can be seen here: http://www.linuxtv.org/wiki/index.php/User:Hlangos In my understanding we should found some balance between URB size and transferred stream bandwidth. For example DVB-T stream, when common transmission parameters are used, is more than 20Mbit/sec. There is also USB bridge chips which does have two or more different standard frontends needed different stream bandwidths. Should we add new module param for override module default? a800 BULK 7x 4096= 28672 af9005 BULK 10x 4096= 40960 USB1.1 BUGFIX: x512=>x188 af9015 BULK 6x 3072= 3072 BUGFIX: x512=>x188 anysee BULK 8x 512= 4096 ce6230 BULK 6x 512= 3072 cinergyT2 BULK 5x 512= 2560 cxusb BULK 5x 8192= 40960 cxusb BULK 7x 4096= 28672 dib0700 BULK 4x39480=157920 210x188 !!HUGE!! dibusb-mb BULK 7x 4096= 28672 56x512 dibusb-mc BULK 7x 4096= 28672 digitv BULK 7x 4096= 28672 dtt200u BULK 7x 4096= 28672 dtv5100 BULK 8x 4096= 32768 dw2102 BULK 8x 4096= 32768 gl861 BULK 7x 512= 3584 gp8psk BULK 7x 8192= 57344 m920x BULK 8x 512= 4096 m920x BULK 8x16384=131072 256x512 !!HUGE!! nova-t-usb2 BULK 7x 4096= 28672 opera1 BULK 10x 4096= 40960 umt-010 BULK 10x 512= 5120 vp702x BULK 10x 4096= 40960 vp7045 BULK 7x 4096= 28672 au6610 ISOC 5 frames 40 size 942 ttusb2 ISOC 5 frames 4 size 942 regards Antti -- http://palosaari.fi/