Re: txqueuelen has wrong units; should be time

Eric Dumazet
2011-02-27T07:54:20Z

Le dimanche 27 février 2011 à 08:02 +0100, Mikael Abrahamsson a écrit :
> On Sun, 27 Feb 2011, Albert Cahalan wrote:
>
> > Nanoseconds seems fine; it's unlikely you'd ever want
> > more than 4.2 seconds (32-bit unsigned) of queue.
>
> I think this is shortsighted and I'm sure someone will come up with a case
> where 4.2 seconds isn't enough. Let's not build in those kinds of
> limitations from start.
>
> Why not make it 64bit and go to picoseconds from start?
>
> If you need to make it 32bit unsigned, I'd suggest to start from
> microseconds instead. It's less likely someone would want less than a
> microsecond of queue, than someone wanting more than 4.2 seconds of queue.
>

32 or 64 bits doesnt matter a lot. At Qdisc stage we have up to 40 bytes
available in skb->sb[] for our usage.

Problem is some machines have slow High Resolution timing services.

_If_ we have a time limit, it will probably use the low resolution (aka
jiffies), unless high resolution services are cheap.

I was thinking not having an absolute hard limit, but an EWMA based one.