From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14256 invoked by alias); 20 Feb 2006 18:09:32 -0000 Received: (qmail 14247 invoked by uid 22791); 20 Feb 2006 18:09:31 -0000 X-Spam-Check-By: sourceware.org Received: from snape.ecoscentric.com (HELO snape.ecoscentric.com) (212.13.207.199) by sourceware.org (qpsmtpd/0.31) with ESMTP; Mon, 20 Feb 2006 18:09:26 +0000 Received: by snape.ecoscentric.com (Postfix, from userid 99) id A94FFDC8724; Mon, 20 Feb 2006 18:09:24 +0000 (GMT) Received: from delenn.bartv.net (snape.ecoscentric.com [212.13.207.199]) by snape.ecoscentric.com (Postfix) with ESMTP id 76A54DC8722; Mon, 20 Feb 2006 18:09:22 +0000 (GMT) To: derek.bouius@sympatico.ca Cc: ecos-discuss@sourceware.org In-reply-to: <20060220173456.MNZU28670.tomts13-srv.bellnexxia.net@derekwin> (derek.bouius@sympatico.ca) From: Bart Veer References: <20060220173456.MNZU28670.tomts13-srv.bellnexxia.net@derekwin> Message-Id: <20060220180922.76A54DC8722@snape.ecoscentric.com> Date: Mon, 20 Feb 2006 18:09:00 -0000 Mailing-List: contact ecos-discuss-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: ecos-discuss-owner@ecos.sourceware.org Subject: Re: [ECOS] How to debug synchronisation in the usbs.c in a new usb-driver for the ARM at91sam7s... X-SW-Source: 2006-02/txt/msg00202.txt.bz2 >>>>> "Derek" == Derek Bouius writes: Derek> I tested the below patch and it works. Derek> The throughput performance change compared to using a Derek> semaphore (in our system) is Derek> usbs_devtab_cwrite : 17% drop Derek> usbs_devtab_cread : 53% drop Derek> which is quite significant! Very significant - but I am rather sceptical. Granted, semaphores will be more efficient. However for USB communication throughput is constrained by the host and by USB's millisecond frames. A massive performance difference like the above would imply that a lot of transfers are now being pushed into the next frame. That is possible if the eCos target's performance is borderline when it comes to feeding data to the host, but it would be a bit of a coincidence. Are you sure that there are no other differences, e.g. debug vs. production builds? Bart -- Bart Veer eCos Configuration Architect http://www.ecoscentric.com/ The eCos and RedBoot experts -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss