tcpdump mailing list archives
Re: [PATCH] Add ioctl to disable bpf timestamping
From: Guy Harris <guy () alum mit edu>
Date: Wed, 8 Sep 2004 12:00:29 -0700
On Sep 8, 2004, at 2:26 AM, Bruce M Simpson wrote:
Here's a patch against 5.3 to add a per-instance switch which allows the user to specify if captured packets should be timestamped (and, if so, whether microtime() or the faster but less accurate getmicrotime() call should be used).
This is probably a pointless optimization, as you probably relatively rarely have multiple BPF devices bound to the same interface receiving the bulk of the packets (as opposed to some daemon with a filter that passes only the packets it's interested in), but would there be any advantage to having "bpf_tap()" and "bpf_mtap()" fetch the time stamp and pass that to "catchpacket()", so that in the case where there *is* more than one tap, the time stamp is only fetched once?
That has the "disadvantage" that a tap might get a more accurate time stamp than it needs (the most accurate time stamp requested by a BPF device would be the one used).
Comments/flames/etc to the usual...
If this is generally accepted as a good idea, it might be worth mentioning it to the other BSDs.
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Current thread:
- [PATCH] Add ioctl to disable bpf timestamping Bruce M Simpson (Sep 08)
- Re: [PATCH] Add ioctl to disable bpf timestamping Guy Harris (Sep 08)
- Re: [PATCH] Add ioctl to disable bpf timestamping Guy Harris (Sep 08)
- Re: [PATCH] Add ioctl to disable bpf timestamping Darren Reed (Sep 25)
- Re: [PATCH] Add ioctl to disable bpf timestamping Matthew Luckie (Sep 25)
- Re: [PATCH] Add ioctl to disable bpf timestamping Guy Harris (Sep 25)
- Re: [PATCH] Add ioctl to disable bpf timestamping Guy Harris (Sep 08)