From owner-freebsd-net@FreeBSD.ORG Tue Jul 1 03:05:04 2008 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E65F4106567D for ; Tue, 1 Jul 2008 03:05:04 +0000 (UTC) (envelope-from sepherosa@gmail.com) Received: from an-out-0708.google.com (an-out-0708.google.com [209.85.132.251]) by mx1.freebsd.org (Postfix) with ESMTP id 992408FC0C for ; Tue, 1 Jul 2008 03:05:04 +0000 (UTC) (envelope-from sepherosa@gmail.com) Received: by an-out-0708.google.com with SMTP id b33so385993ana.13 for ; Mon, 30 Jun 2008 20:05:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=PL+8lZ0zGKyaatfkZrSjVMInwCzhLUxLyP8jIT/B5tk=; b=hsH9O76O7tnFqjCf0wkuCte/T2ccW8iZ+WZ2yNfSskbqAgpqXxUKGULpjG8rhEp49Q 4fzteawWj5ysxsE6sco7/JOpt7KSwAWdTXE0SYph1sfQ/ZLrBrOGrbhQrA98VKXQLo6h vpmrTyaRiBD+uizfZ8eNMULLzuPKONop8amlU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=r8JPPpQWbXOAoprqGIRYVbZnZsN8N7qVQKhzfc78M344esV/MIObD1wrjwRzuDp2ne 4LqGm/IaD+xE6e6QA/pWA9OEMhJlah4flIm74TL6JAhBlWNa85hK+iqrqLNAD3VaSQ1E Fd2L8fudUAaREcOkfvo7O98q/snKyk4/+OkPY= Received: by 10.100.194.5 with SMTP id r5mr5111215anf.2.1214881503109; Mon, 30 Jun 2008 20:05:03 -0700 (PDT) Received: by 10.100.107.6 with HTTP; Mon, 30 Jun 2008 20:05:03 -0700 (PDT) Message-ID: Date: Tue, 1 Jul 2008 11:05:03 +0800 From: "Sepherosa Ziehau" To: Paul In-Reply-To: <48699960.9070100@gtcomm.net> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <4867420D.7090406@gtcomm.net> <200806301944.m5UJifJD081781@lava.sentex.ca> <20080701004346.GA3898@stlux503.dsto.defence.gov.au> <20080701010716.GF3898@stlux503.dsto.defence.gov.au> <486986D9.3000607@monkeybrains.net> <48699960.9070100@gtcomm.net> Cc: freebsd-net@freebsd.org, Ingo Flaschberger , "Wilkinson, Alex" , "Support \(Rudy\)" Subject: Re: Freebsd IP Forwarding performance (question, and some info) [7-stable, current, em, smp] X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Jul 2008 03:05:05 -0000 On 7/1/08, Paul wrote: > All the NIC drivers in 7 pretty much use interrupt moderation so it can I am not quite sure whether em(4)'s RX interrupt moderation works as expected or not. But, AFAIK, nfe(4) and re(4) does not have RX interrupt moderation. Their TX interrupt moderation could be mimiced by using their hardware timer and disabling their TX interrupt. The lacking of RX im is difficult to handle, I could imagine following way: - During init, enable RX intr - When RX intr comes, disable RX intr and set up hardware timer intr - When timer intr comes and no RX happens, disable timer intr and enable RX intr Properly configured #RX desc and timer intr interval will be required to make sure that the RX desc collection could keep up with the hardware speed. I used pure timer intr (8000Hz) on nfe(4) in dfly w/ good result, i.e. TX/RX @linespeed without livelocking the system. The drawback of pure timer intr is that you waste extra cpu power, when there is nothing to process. > never lock the machine anyway.. This effectively kills polling and it really > no longer has any use except to be able to have a fraction of the cpu set Oh? Really? :] Best Regards, sephe -- Live Free or Die