From owner-freebsd-current@FreeBSD.ORG Wed Apr 11 04:09:53 2012 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id D4E7A106566C for ; Wed, 11 Apr 2012 04:09:53 +0000 (UTC) (envelope-from jhellenthal@dataix.net) Received: from mail-iy0-f182.google.com (mail-iy0-f182.google.com [209.85.210.182]) by mx1.freebsd.org (Postfix) with ESMTP id 8977C8FC23 for ; Wed, 11 Apr 2012 04:09:53 +0000 (UTC) Received: by iahk25 with SMTP id k25so891088iah.13 for ; Tue, 10 Apr 2012 21:09:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dataix.net; s=rsa; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to; bh=Zufs5q6xnWQp9SYx7MnO6ReeuRHBjoMxbFQgjJ3URGg=; b=R3+phvJKlWF8d5cDJD3ZyHuJitD942n/1KaY82ASoQLbyZpq13RXJT1uuyTy3MHWpM GpD8qrJzyFgAtCQcuXVGDdWM2WOXgyjar/iyNZzMfwlZxkR9GjUKQJkJ59UvQgeifHyJ 9SPkqUHbTNtPKhy6L8AHX+/RuLv817jTa9Ce8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:x-gm-message-state; bh=Zufs5q6xnWQp9SYx7MnO6ReeuRHBjoMxbFQgjJ3URGg=; b=M4YcjmFmAUjp9ce8Ku2e4yyD2kRKzZ1En4f/GjEY/Pw3zSgYQVbV1iwBxbw6xMu29V lukq5fTSYxasG43mMblpwZzZUuVOnkbzEEHQ+nFtXcTRYM2D931KdTPsSP67oAT/dsdw ev+KdlyHc49MhvCtqJcn9uEBqUK9b4B4q95+fTCsQR2ulXuGtOk3PmVTuRl2Ins+cqfv qep1x6C7yx3wAkDy4BsonS5jQ0QFQJ0mUuxOIaqdTZSC/QUw22bUnJRcvmu40WVrcItE yb1snc7R+jLeGxZfC2HR6880z7ceOPD091GVCZ0S5r3Hb0aMBIEV35vLbCi0NPB9OyWo NOiA== Received: by 10.50.154.169 with SMTP id vp9mr784115igb.53.1334117392759; Tue, 10 Apr 2012 21:09:52 -0700 (PDT) Received: from DataIX.net (adsl-99-181-142-73.dsl.klmzmi.sbcglobal.net. [99.181.142.73]) by mx.google.com with ESMTPS id i6sm4067643igq.3.2012.04.10.21.09.51 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 10 Apr 2012 21:09:52 -0700 (PDT) Received: from DataIX.net (localhost [127.0.0.1]) by DataIX.net (8.14.5/8.14.5) with ESMTP id q3B49oFa026333 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 11 Apr 2012 00:09:50 -0400 (EDT) (envelope-from jhellenthal@DataIX.net) Received: (from jhellenthal@localhost) by DataIX.net (8.14.5/8.14.5/Submit) id q3B49mgM026332; Wed, 11 Apr 2012 00:09:48 -0400 (EDT) (envelope-from jhellenthal@DataIX.net) Date: Wed, 11 Apr 2012 00:09:48 -0400 From: Jason Hellenthal To: Luigi Rizzo Message-ID: <20120411040948.GA24775@DataIX.net> References: <20120410225257.GB53350@onelab2.iet.unipi.it> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120410225257.GB53350@onelab2.iet.unipi.it> X-Gm-Message-State: ALoCoQkfgQcwTBXTLm3upAbN8mK87yA2k2I0TWsMuiKCrsZvd6y/dk0/1C0kvlczE/HSXnhM6k/D Cc: current@freebsd.org, net@freebsd.org Subject: Re: strange ping response times... X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 11 Apr 2012 04:09:53 -0000 On Wed, Apr 11, 2012 at 12:52:57AM +0200, Luigi Rizzo wrote: > I noticed this first on a 10G interface, but now there seems > to be a similar issue on the loopback. > > Apparently a ping -f has a much lower RTT than one with non-zero > delay between transmissions. Part of the story could be that > the flood version invokes a non-blocking select. > On the other hand, pinging on the loopback should make > the response available right away, so what could be the reason > for the additional 3..10us in the ping response time ? > > The following are numbers on an i7-2600k at 3400 MHz + turboboost, > running stable/9 amd64. Note how the min ping time significantly > increases moving from flood to 10ms to 1s. > On an Intel 10G interface i am seeing a min of 14-16us with Sorry but I am having trouble wrapping my head around this as the results below are only for the loopback address 127.0.0.1 that does not travel on the wire at all ? Did you assign this to the 10ge interface ? if so which result is which. ? In order to get any good results on my machine I had to tune the following. net.inet.icmp.reply_from_interface=1 net.inet.icmp.icmplim_output=0 net.inet.icmp.icmplim=0 net.inet.icmp.log_redirect=1 You may have other options if this is greater than stable/8 @ 234095 But yes the results seem skewed to some extent and being loopback I would think there should be a very near zero rx/tx time. > a ping flood, and up to 33-35us with the standard 1s interval > (using -q probably trims another 2..5us) > > > sudo ping -c 1000 -q -f 127.0.0.1 > round-trip min/avg/max/stddev = 0.002/0.003/0.012/0.001 ms > > sudo ping -c 1000 -q -f 127.0.0.1 > round-trip min/avg/max/stddev = 0.002/0.002/0.013/0.001 ms > > sudo ping -c 1000 -q -f 127.0.0.1 > round-trip min/avg/max/stddev = 0.002/0.002/0.013/0.001 ms > > sudo ping -c 10000 -q -f 127.0.0.1 > round-trip min/avg/max/stddev = 0.002/0.002/0.011/0.001 ms > > > sudo ping -c 1000 -q -i 0.01 127.0.0.1 > round-trip min/avg/max/stddev = 0.005/0.012/0.017/0.001 ms > > sudo ping -c 1000 -q -i 0.01 127.0.0.1 > round-trip min/avg/max/stddev = 0.004/0.012/0.016/0.001 ms > > sudo ping -c 200 -q -i 0.01 127.0.0.1 > round-trip min/avg/max/stddev = 0.007/0.012/0.017/0.002 ms > > sudo ping -c 200 -q -i 0.01 127.0.0.1 > round-trip min/avg/max/stddev = 0.005/0.012/0.018/0.002 ms > > sudo ping -c 200 -q -i 0.01 127.0.0.1 > round-trip min/avg/max/stddev = 0.009/0.012/0.020/0.002 ms > > sudo ping -c 200 -q -i 0.01 127.0.0.1 > round-trip min/avg/max/stddev = 0.006/0.012/0.016/0.001 ms > > > sudo ping -c 200 -q -i 0.1 127.0.0.1 > round-trip min/avg/max/stddev = 0.007/0.014/0.020/0.001 ms > > sudo ping -c 200 -q -i 0.1 127.0.0.1 > round-trip min/avg/max/stddev = 0.006/0.014/0.019/0.002 ms > > sudo ping -c 200 -q -i 0.1 127.0.0.1 > round-trip min/avg/max/stddev = 0.007/0.014/0.021/0.001 ms > > sudo ping -c 200 -q -i 0.1 127.0.0.1 > round-trip min/avg/max/stddev = 0.007/0.014/0.020/0.001 ms > > sudo ping -c 200 -q -i 0.1 127.0.0.1 > round-trip min/avg/max/stddev = 0.006/0.014/0.021/0.002 ms > > sudo ping -c 200 -q -i 0.1 127.0.0.1 > round-trip min/avg/max/stddev = 0.010/0.014/0.022/0.001 ms > > > sudo ping -c 20 -q -i 1 127.0.0.1 > round-trip min/avg/max/stddev = 0.013/0.018/0.022/0.002 ms > > sudo ping -c 20 -q -i 1 127.0.0.1 > round-trip min/avg/max/stddev = 0.012/0.018/0.021/0.002 ms > > sudo ping -c 20 -q -i 1 127.0.0.1 > round-trip min/avg/max/stddev = 0.009/0.017/0.018/0.002 ms > > sudo ping -c 20 -q -i 1 127.0.0.1 > round-trip min/avg/max/stddev = 0.011/0.017/0.021/0.002 ms > > sudo ping -c 20 -q -i 1 127.0.0.1 > round-trip min/avg/max/stddev = 0.010/0.017/0.020/0.002 ms > > sudo ping -c 20 -q -i 1 127.0.0.1 > round-trip min/avg/max/stddev = 0.009/0.017/0.028/0.004 ms > > cheers > luigi > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" -- ;s =;