Date: Wed, 13 Jan 1999 14:03:49 -0800 (PST) From: Doug White <dwhite@pond.net> To: Bill Fenner <fenner@parc.xerox.com> Cc: hackers@FreeBSD.ORG Subject: Re: using raw sockets Message-ID: <Pine.BSF.3.96.990113134803.7816B-100000@guppy.pond.net> In-Reply-To: <199901130039.QAA06354@mango.parc.xerox.com>
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On Tue, 12 Jan 1999, Bill Fenner wrote: > In message <Pine.BSF.3.96.990112153755.6791A-100000@guppy.pond.net>you write: > >I'm assuming the timestamps are generated by tcpdump, > >or are they the real packet timestamps? > > The timestamp that tcpdump prints is the timestamp that bpf attaches > (i.e. when the driver calls bpf_[m]tap() ). Hm, I'll have to look at that. It might be a peculiarity with the ep driver. I want to try a de card and see what I get. > Can you compare that timestamp against gettimeofday(), to see if it > looks like the latency is in the bpf buffer? > >From a brief inspection of the bpf code, it looks like bpf won't > wake up a selecting process until the buffer is almost full. Have > you tried using the BIOCIMMEDIATE ioctl? Assuming I did the ioctl right, it is set. Doug White | Pacific Crest Networks Internet: dwhite@pond.net | http://www.pond.net/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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