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From devnull@lkml.org Tue Apr 23 22:26:25 2024 Delivery-date: Tue, 15 Aug 2006 11:34:48 +0000 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965372AbWHOLeV (ORCPT ); Tue, 15 Aug 2006 07:34:21 -0400 Received: from spirit.analogic.com ([204.178.40.4]:56849 "EHLO spirit.analogic.com") by vger.kernel.org with ESMTP id S965370AbWHOLeU convert rfc822-to-8bit (ORCPT ); Tue, 15 Aug 2006 07:34:20 -0400 Received: from chaos.analogic.com ([10.112.50.11]) by phoenix.analogic.com with Microsoft SMTPSVC(6.0.3790.211); Tue, 15 Aug 2006 07:34:18 -0400 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-MimeOLE: Produced By Microsoft Exchange V6.5.7226.0 Received: from chaos.analogic.com (localhost [127.0.0.1]) by chaos.analogic.com (8.12.11/8.12.11) with ESMTP id k7FBYIuE028986; Tue, 15 Aug 2006 07:34:18 -0400 Received: (from linux-os@localhost) by chaos.analogic.com (8.12.11/8.12.11/Submit) id k7FBYHFI028985; Tue, 15 Aug 2006 07:34:17 -0400 X-OriginalArrivalTime: 15 Aug 2006 11:34:18.0280 (UTC) FILETIME=[BE89D280:01C6C05E] content-class: urn:content-classes:message Subject: Re: Network compatibility and performance Date: Tue, 15 Aug 2006 07:34:17 -0400 Message-Id: In-Reply-To: <44E0EA5E.30306@candelatech.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Network compatibility and performance Thread-Index: AcbAXr6TXbuZJM/JTaeENJNzqeH5kQ== References: <44DE2A44.5070006@candelatech.com> <44E0EA5E.30306@candelatech.com> From: "linux-os \(Dick Johnson\)" To: "Ben Greear" Cc: "Linux kernel" Reply-To: "linux-os \(Dick Johnson\)" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 14 Aug 2006, Ben Greear wrote: > linux-os (Dick Johnson) wrote: > >> No it will return FAIL (-1) or an error and 0 (the bottom of the procedure) >> if the whole things went. It is mandatory that the whole thing goes >> so this procedure should handle any intermediate actions. > > I see..I missed that part. > >> Upon your advice, I may try to add select() although, on a write it >> seems to be putting in user-space something that used to be handled >> quite well in the kernel. I don't think the user should really care >> about the kernel internals, whether or not the kernel happens to have >> a buffer available. > > Since you put it in non-blocking mode, you need the select() to throttle > unless you want to busy spin. Whether you should have to actually put > in in non-blocking mode or not is a different question. > >>> I have no idea why you need to add the MIN() logic..and that seems like >>> something that should not be required. >>> >> >> It seems that some code 'thinks' that a large buffer of data is >> an error and won't even try to send some anymore. > > I have seen a problem where I can repeatedly hang a TCP connection > when running at high speed. The tx queue is full or mostly full, and > on the wire I only see 200kpps of duplicate acks. Can't reproduce it > with anything other than my big complicated proprietary app, so it > remains unfixed. > > I am not sure if this is related to what you see or not..but could you > check to see if there is lots of acks on the wire when this hang happens? I will check to see what it's doing on the wire and get back. > >>> Even 112kbps sucks on a decent network. What is the speed of your >>> network, what protocol are you using, if tcp, what is the latency >>> of your network? >>> >> >> >> The network is a single wire about 8 feet long, connecting Intel gigibit >> links on two identical computers (crossover cable). This link is TCP. >> For high-speed data, I use UDP and I get a higher throughput because >> there is no handshake. Thew latency is the latency of Linux. BTW, it's >> only a gigaBIT link, you can divide that by 8 for gigabytes. I don't >> know the actual bit-rate on the wires, if we assume 1GHz, the byte-rate >> is only 125,000 bytes per second. Being able to use 89.6 percent of >> that isn't bad at all. > > You must be meaning to add a few more zeros to that number. If you > are getting ~125,000,000 Bytes per second then you are doing OK. > ACK that! > Ben > > Cheers, Dick Johnson Penguin : Linux version 2.6.16.24 on an i686 machine (5592.62 BogoMips). 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