Date: Fri, 25 May 2012 14:02:37 -0700 From: Kevin Oberman <kob6558@gmail.com> To: Andrew Gallatin <gallatin@cs.duke.edu> Cc: freebsd-net@freebsd.org, Andrew Gallatin <gallatin@myri.com> Subject: Re: Major performance hit with ToS setting Message-ID: <CAN6yY1s=xD75LP19SzhzZX5iP_ZpHvYbYegc05X9YC3ZtXzOZw@mail.gmail.com> In-Reply-To: <4FBF88CE.20209@cs.duke.edu> References: <CAN6yY1sLxFJ18ANO7nQqLetnJiT-K6pHC-X3yT1dWuWGa0VLUg@mail.gmail.com> <4FBF88CE.20209@cs.duke.edu>
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On Fri, May 25, 2012 at 6:27 AM, Andrew Gallatin <gallatin@cs.duke.edu> wro= te: > On 05/24/12 18:55, Kevin Oberman wrote: > >> >> This is,of course, on a 10G interface. On 7.3 there is little > > > Hi Kevin, > > > What you're seeing looks almost like a checksum is bad, or > there is some other packet damage. =A0Do you see any > error counters increasing if you run netstat -s before > and after the test & compare the results? > > Thinking that, perhaps, this was a bug in my mxge(4), I attempted > to reproduce it this morning between =A08.3 and 9.0 boxes and > failed to see the bad behavior.. > > % nuttcp-6.1.2 -c32t -t diablo1-m < /dev/zero > =A09161.7500 MB / =A010.21 sec =3D 7526.5792 Mbps 53 %TX 97 %RX 0 host-re= trans > 0.11 msRTT > % nuttcp-6.1.2 =A0-t diablo1-m < /dev/zero > =A09140.6180 MB / =A010.21 sec =3D 7509.8270 Mbps 53 %TX 97 %RX 0 host-re= trans > 0.11 msRTT > > > However, I don't have any 8.2-r box handy, so I cannot > exactly repro your experiment... As seems to always be the case, the test system I set up to try other versions of FreeBSD does not exhibit the problem. I have no difficulty generating traffic at speeds above 1G. (I saw a max on one run over just a few miles of over 9G.) So I am scratching my head and re-testing this. FWIW, three different engineers tested production systems and all saw the same issue, whether using nuttcp or iperf. If I run hte tests now on one of those systems, I see the problem. So I am off to do a bunch more testing and I'll try to have some real information soon. Thanks for looking into this. --=20 R. Kevin Oberman, Network Engineer E-mail: kob6558@gmail.com
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