Date: Thu, 24 May 2012 17:48:23 -0700 From: Kevin Oberman <kob6558@gmail.com> To: "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net> Cc: net@freebsd.org Subject: Re: Major performance hit with ToS setting Message-ID: <CAN6yY1tSLqQMg5LqrPOJ32Y2S2f65yhhCPOdn5VU0NL=VXvONg@mail.gmail.com> In-Reply-To: <FC59CF19-C3BD-4906-8338-C18AC5DC6867@lists.zabbadoz.net> References: <CAN6yY1sLxFJ18ANO7nQqLetnJiT-K6pHC-X3yT1dWuWGa0VLUg@mail.gmail.com> <FC59CF19-C3BD-4906-8338-C18AC5DC6867@lists.zabbadoz.net>
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On Thu, May 24, 2012 at 4:43 PM, Bjoern A. Zeeb <bzeeb-lists@lists.zabbadoz.net> wrote: > On 24. May 2012, at 22:55 , Kevin Oberman wrote: > >> When we set the ToS bits for less than best effort (also called >> scavenger) on packets (ToS=3D32), performance on FreeBSD 8.2 is >> terrible. It was as good as best effort on FreeBSD 7.3 (assuming no >> congestion). I will look into what 9 does, but does anyone have an >> idea of why 8.2 behaves so badly when ToS is set to 32? >> Here is an example of what happens to performance: >> nuttcp with ToS=3D0: >> 622.5000 MB / =A0 1.00 sec =3D 5221.7570 Mbps >> 623.3125 MB / =A0 1.00 sec =3D 5228.5883 Mbps >> 624.0000 MB / =A0 1.00 sec =3D 5234.4495 Mbps >> >> With ToS=3D32 (0x20): >> 0.3750 MB / =A0 1.00 sec =3D =A0 =A03.1457 Mbps >> 0.5000 MB / =A0 1.00 sec =3D =A0 =A04.1942 Mbps >> 0.5000 MB / =A0 1.00 sec =3D =A0 =A04.1942 Mbps >> >> This is,of course, on a 10G interface. On 7.3 there is little >> difference between the two. We are using cubic CC on the 8.2 system. > > This looks like a different problem than just TOS. =A0I assume however > that not setting the TOS you get the same as expected performance? > > Which NIC? The two nuttcp runs were identical and we got similar results with iperf. All tests were using Myricom (mxge) cards. --=20 R. Kevin Oberman, Network Engineer E-mail: kob6558@gmail.com
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