From owner-freebsd-net@FreeBSD.ORG Mon Oct 3 08:20:46 2011 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 10A2A106564A for ; Mon, 3 Oct 2011 08:20:46 +0000 (UTC) (envelope-from jfvogel@gmail.com) Received: from mail-wy0-f182.google.com (mail-wy0-f182.google.com [74.125.82.182]) by mx1.freebsd.org (Postfix) with ESMTP id 859E88FC0A for ; Mon, 3 Oct 2011 08:20:45 +0000 (UTC) Received: by wyj26 with SMTP id 26so3867737wyj.13 for ; Mon, 03 Oct 2011 01:20:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=e3CWFvVGrX7aYKxJn4X+pHaaOeL8SUPIeSIKVGxIKn0=; b=jtnizmInOehAL+MOpPwDdkLZpt2c6O2CsyIafv+4xi+tvmOU0V2WpU6mKNrSGzmZzn ilhEwjQjK9PWp14czTWajGyod7DO5HntLUlK3O9DhrHnEWMn3DiJllVXd1OYymcKaztG pSGCEyLSO+/vwY95Ro/YaSbVHG8CWTLtTwzR8= MIME-Version: 1.0 Received: by 10.227.42.136 with SMTP id s8mr1492169wbe.28.1317630044400; Mon, 03 Oct 2011 01:20:44 -0700 (PDT) Received: by 10.180.106.35 with HTTP; Mon, 3 Oct 2011 01:20:44 -0700 (PDT) In-Reply-To: <4E896999.3020001@sepehrs.com> References: <4E886A3B.7000502@sepehrs.com> <4E896999.3020001@sepehrs.com> Date: Mon, 3 Oct 2011 01:20:44 -0700 Message-ID: From: Jack Vogel To: Hooman Fazaeli Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: "freebsd-net@freebsd.org" Subject: Re: em(4) high latency w/o msix 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: Mon, 03 Oct 2011 08:20:46 -0000 Can you try the driver in 8.2 and possibly stable/8 to see the behavior there. And, just curious, why are you disabling MSIX? Jack On Mon, Oct 3, 2011 at 12:51 AM, Hooman Fazaeli wrote: > ** > Hi Jack > > The hardware is a PCIe network appliance with 3 port modules. The ports I > have > used in the test are 82574L residing on a 4 port module. Anyway, as I noted > in last mail, the stock 7.3-RELEASE driver does not expose this problem on > the same hardware. > > > On 10/2/2011 7:38 PM, Jack Vogel wrote: > > On what hardware? > > Jack > > > On Sun, Oct 2, 2011 at 6:42 AM, Hooman Fazaeli wrote: > >> >> Latest em(4) driver from HEAD seems to have high latency >> when MSIX is disabled. >> >> With MSIX enabled (hw.em.enable_msix=1): >> >> # ping -c5 192.168.1.83 >> PING 192.168.1.83 (192.168.1.83): 56 data bytes >> 64 bytes from 192.168.1.83: icmp_seq=0 ttl=64 time=0.055 ms >> 64 bytes from 192.168.1.83: icmp_seq=1 ttl=64 time=0.076 ms >> 64 bytes from 192.168.1.83: icmp_seq=2 ttl=64 time=0.066 ms >> 64 bytes from 192.168.1.83: icmp_seq=3 ttl=64 time=0.051 ms >> 64 bytes from 192.168.1.83: icmp_seq=4 ttl=64 time=0.063 ms >> >> --- 192.168.1.83 ping statistics --- >> 5 packets transmitted, 5 packets received, 0.0% packet loss >> round-trip min/avg/max/stddev = 0.051/0.062/0.076/0.009 ms >> >> With MSIX disabled: >> >> # ping -c5 192.168.1.83 >> PING 192.168.1.83 (192.168.1.83): 56 data bytes >> 64 bytes from 192.168.1.83: icmp_seq=0 ttl=64 time=0.180 ms >> 64 bytes from 192.168.1.83: icmp_seq=1 ttl=64 time=0.164 ms >> 64 bytes from 192.168.1.83: icmp_seq=2 ttl=64 time=0.169 ms >> 64 bytes from 192.168.1.83: icmp_seq=3 ttl=64 time=0.172 ms >> 64 bytes from 192.168.1.83: icmp_seq=4 ttl=64 time=0.167 ms >> >> --- 192.168.1.83 ping statistics --- >> 5 packets transmitted, 5 packets received, 0.0% packet loss >> round-trip min/avg/max/stddev = 0.164/0.170/0.180/0.005 ms >> >> As you see, w/o MSIX, RTT increases by a factor of 3. >> >> I also tested the following drivers: >> - igb(4) from HEAD: OK. >> - Stock 7.3-RELEASE: OK. >> - Stock 7.4-RELEASE: problem exist. >> >> Any ideas? >> >> >> >> >> >