Date: Tue, 12 Jan 1999 16:39:40 PST From: Bill Fenner <fenner@parc.xerox.com> To: Doug White <dwhite@pond.net> Cc: Bill Fenner <fenner@parc.xerox.com>, hackers@FreeBSD.ORG Subject: Re: using raw sockets Message-ID: <199901130039.QAA06354@mango.parc.xerox.com> In-Reply-To: Your message of "Tue, 12 Jan 1999 15:43:47 PST." <Pine.BSF.3.96.990112153755.6791A-100000@guppy.pond.net>
next in thread | previous in thread | raw e-mail | index | archive | help
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() ). 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? Bill To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199901130039.QAA06354>