Date: Sat, 28 Feb 2004 21:23:43 -0500 From: Deepak Jain <deepak@ai.net> To: Don Bowman <don@sandvine.com> Cc: freebsd-hackers@freebsd.org Subject: Re: em0, polling performance, P4 2.8ghz FSB 800mhz Message-ID: <40414D2F.6070604@ai.net> In-Reply-To: <FE045D4D9F7AED4CBFF1B3B813C85337045D8305@mail.sandvine.com> References: <FE045D4D9F7AED4CBFF1B3B813C85337045D8305@mail.sandvine.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Don Bowman wrote: >>I have a machine running 4.9. P4 2.8Ghz, 800mhz bus, Intel PRO/1000 >>ethernet connected to a Cisco, both sides are locked to 1000/FD. >> >>The kernel has HZ=1000, and DEVICE_POLLING, IPFW, DUMMYNET, >>etc. After >>only a few minutes of run time under an attack ~90,000 pps. >>The attack >>has been limited at the router to JUST incoming TCP port 80 inbound >>traffic. I don't know why the machine is having such a hard >>time under >>the load. The cpu shows it is >90% idle even under the worst of the >>attack. What am I doing wrong? > > > I think there's a problem with CPU time not getting properly > accounted for in device polling, so it may be busier than you think. > > For this scenario, i would set net.inet.tcp.blackhole=2. You > might be spending a lot of time creating the ICMP unreachable > messages, rather than in the network driver (where device polling > would help). > I'd like to know more about the CPU time idea. I have net.inet.udp.blackhole=2 and net.inet.tcp.blackhole=2 because I saw a lot of dstunreachable packets out. The system can hyperthread, but I thought the singlethreading of polling might have been an issue, so I recompiled the kernel without SMP. DJ
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?40414D2F.6070604>