Re: Packet timestamps (was: Re: Network performance degradation from 2.6.11.12 to 2.6.16.20)

Eric Dumazet
2007-03-06T15:16:28Z

On Tuesday 06 March 2007 15:43, Vladimir B. Savkin wrote:
> On Tue, Mar 06, 2007 at 03:38:44PM +0100, Eric Dumazet wrote:
> > 2) "accurate_timestamps" is misleading.
> > Should be "disable_timestamps"
>
> Not, if default is 1, as in my patch.

Yes I saw this. I should write more words next time :)

Full explanation:
----------------------

If your tunable is named "accurate_timestamps" then a 0 value would mean :

Use a low precision timestamp (based on xtime for example) instead of a full
resolution...

This is not what your patch does (while it could do that, but beware that
net-2.6.22 includes now a ktime_t timestamping)

So :
------

It would be better to name the tunable "disable_timestamps", default 0 of
course....
It would better describe what your patch is actually doing : Even if a tcpdump
is running (so asking for timestamps), it wont have them because the sysctl
disabled them.

Thank you