[Click] FromDevice (OS-X) buffering up packets...

[rchertov at cs.ucsb.edu]

On 5:25 pm 07/19/10 <rchertov at cs.ucsb.edu> wrote:
> I am seeing similar behavior on Linux as well.  In my case, I carry some

Just wanted to state that the behavior on Linux is similar but not as bad
as Nick is reporting for OSX.  I get about 20ms worth of extra jitter by
using the To/FromDevice compared to sending the data via the RawSocket.

> data between two PCs which run user-level click.  If I use RawSocket
> element, I get much better performance compared to using To/FromDevice
> and manually composing the frames.
> 
> 
> On 10:42 am 07/19/10 Nicholas Weaver <nweaver at icsi.berkeley.edu> wrote:
> > The test configuration:
> > 
> > FromDevice(en0, PROMISC true) -> CheckIPHeader(14) ->
> >            IPPrint('reply') -> Discard;
> > 
> > 
> > A TCPdump running at the same time gets all the packets as they are
> > received, but the click configuration gets them in bursts (but the
> > timestamps are right)
> > 
> > On Jul 19, 2010, at 10:38 AM, Nicholas Weaver wrote:
> > 
> > > I remember having a similar problem before and I don't remember what
> > > the solution is... 
> > > On OS-X (latest version, latest devtools), FromDevice is buffering
> > > up a large number of packets rather than receiving them in real
> > > time. A TCPdump running at the same time does not have this problem.
> > > 
> > > 
> > > Suggestions?
> > > 
> > > 
> > > 
> > 
> > 
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> > https://amsterdam.lcs.mit.edu/mailman/listinfo/click
> 
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