From owner-freebsd-net@FreeBSD.ORG Fri Jul 3 11:31:44 2009 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 EED291065670 for ; Fri, 3 Jul 2009 11:31:44 +0000 (UTC) (envelope-from barney_cordoba@yahoo.com) Received: from web63907.mail.re1.yahoo.com (web63907.mail.re1.yahoo.com [69.147.97.122]) by mx1.freebsd.org (Postfix) with SMTP id 94BC68FC16 for ; Fri, 3 Jul 2009 11:31:44 +0000 (UTC) (envelope-from barney_cordoba@yahoo.com) Received: (qmail 47405 invoked by uid 60001); 3 Jul 2009 11:31:44 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1246620704; bh=AYA4Vwq2Hye3IOeU7q2iGn0d7YI/FEXcIH0nxjtrnOs=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding; b=Pk2WvbxNXwTyTPT2G9RLW+d4tYGXOTSUdCszOUhTWU0di7AE17gySmW8t0UsnGceRtIbMrpp1mXYSInOlNUHY44wLnxLticXAfg0wO4WdQxzSaffkPCRaJz+3SjREfEOBL/G+zoMzLgefJJRxOmJRtufOL/rUwsuktjhbWGvfzE= DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding; b=PfuFPvhK91yk5Opq2XsQ6IlHGbT/xX1uNHaGT1DdrhEZL24G7vssNiHTMTM6GvNjM5WNt2doOx+xyTAtyd4gUH1cicaTfX6rJzBd5vV3+I5w8xAOt42cSo3VjnhDlgNhs+bsRUEpKSyZRMd0/uFaieKVlcZkIGdPnrGAmldOO6Q=; Message-ID: <117993.46390.qm@web63907.mail.re1.yahoo.com> X-YMail-OSG: 6LPS_vgVM1lzdpchOikAj8Yb7yoXjutofttb1j7UUF9fbHjh9788Zy5pf.OBFXI.rDzUYj16YcaWrCmS8vDSlhJ32bzrCbikLtVlxEcyRCMMyZO_Ep9yUY.UcN97yjLyWOnKNRqj2feSPwpkpQGGazE7HnUXN5LB0yF54SMJz1MHVOA4K_ZZS_h6NbgMuCgtL91QNYQO7roSX587XMfZ8QIYPXcsGrAge18M5MBEDKA929oIOpyfRkhH2n2TFH53Sr_87VcEQYxpjN9Bh24TRyW.A7MURe77QI.gNRyxkiNhTHsuCV8sOvDiAQCpYuAC3339IoAX6dOwf59Q9aE- Received: from [66.176.162.245] by web63907.mail.re1.yahoo.com via HTTP; Fri, 03 Jul 2009 04:31:44 PDT X-Mailer: YahooMailClassic/5.4.17 YahooMailWebService/0.7.289.15 Date: Fri, 3 Jul 2009 04:31:44 -0700 (PDT) From: Barney Cordoba To: Larry Baird MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Cc: freebsd-net@freebsd.org, Paul Thornton Subject: Re: Polling and kern.polling.idle_poll 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: Fri, 03 Jul 2009 11:31:45 -0000 =0A=0A--- On Thu, 7/2/09, Larry Baird wrote:=0A=0A> From: Lar= ry Baird =0A> Subject: Re: Polling and kern.polling.idle_poll= =0A> To: "Barney Cordoba" =0A> Cc: freebsd-net@fr= eebsd.org, "Paul Thornton" =0A> Date: Thursday, July 2, 2009, = 11:31 AM=0A> > Curious as to why you don't=0A> simply lay out the $40 for a= modern ethernet card that=0A> doesn't need polling to work well?=0A> These= are low end embedded boxs.=A0 No way to=0A> upgrade.=A0 But in actuallity= =0A> they have modern (fxp) NICS.=A0 From our testing, live=0A> lock is a r= eal issue=0A> for gateways receiving lots of network traffic.=A0=0A> Pollin= g prevents live=0A> lock.=0A=0AThere are few applications where dropping bu= ckets of packets is preferable to losing the keyboard. If "livelock is a pr= oblem", then your systems are too slow for the task.=0A=0ALivelock can easi= ty be tuned with the "work" parameter. fxp drivers are hard coded to (I thi= nk) 6000 ints per second, so its not rocket science to set your tuning para= meters to whatever the system can handle before entering a livelock scenari= o. In reality, interrupt moderation is the equivalent of polling 6000 times= per second, in the case of fxp. You wouldn't want to set hz to 6000 as you= substantially increase system overhead. Moderation is a much more efficien= t way of managing your ethernet loads, because the "polls" are only directe= d at the driver, and if you dont have traffic then you don't need to get p= olled.=0A=0ABarney=0A=0A=0A