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Re: do_gettimeofday

To: Mitchell Blank Jr <mitch@xxxxxxxxxx>
Subject: Re: do_gettimeofday
From: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Date: Fri, 03 Oct 2003 09:42:19 -0700
Cc: "David S. Miller" <davem@xxxxxxxxxx>, netdev@xxxxxxxxxxx
In-reply-to: <20031003092617.GI42593@gaz.sfgoth.com>
Organization: Candela Technologies
References: <3F7C6F3B.6070502@sgi.com> <20031002125625.72b8c0a7.shemminger@osdl.org> <20031003004133.3148c39a.davem@redhat.com> <20031003082642.GF42593@gaz.sfgoth.com> <20031003012754.23de3f66.davem@redhat.com> <20031003084847.GH42593@gaz.sfgoth.com> <20031003015220.7ee6e451.davem@redhat.com> <20031003092617.GI42593@gaz.sfgoth.com>
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Mitchell Blank Jr wrote:
David S. Miller wrote:

There is the weird issue (with both the sparc64 example and your's
here) of whether we should care about what happens when settimeofday()
occurs.  We probably shouldn't worry about it... as it gives weird
results even currently.


Nah.  If anything you'll get better results since you're computing
the timeval later.

This is another argument for caching the computation though - otherwise
a settimeofday() could cause the packet timestamp to change drasically
from one observation to the next :-)

It would also be nice to be able to set a flag on raw sockets to just have the 'raw' timestamp passed up to user-space. In many cases, the relative timestamp may be all that is needed, and user-space could optimize the conversion to gettimeofday as needed.

Ben


-- Ben Greear <greearb@xxxxxxxxxxxxxxx> Candela Technologies Inc http://www.candelatech.com



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