os206 - slow data transfers

James Cameron quozl at laptop.org
Wed Jul 21 01:54:35 EDT 2010

On Tue, Jul 20, 2010 at 09:01:01AM -0400, Bernie Innocenti wrote:
> El Tue, 20-07-2010 a las 16:26 +1000, James Cameron escribi??:
> > On Mon, Jul 19, 2010 at 11:41:07PM -0500, Mikus Grinbergs wrote:
> > > Earlier, I reported that ethernet data transfers into my XO-1.5 were
> > > now running slower than ethernet data transfers into XO-1 systems.
> > 
> > I've just tested this, though I only had one ethernet device that I
> > could test with.
> James and Mikus: what specific ethernet dongle were you using in these
> tests?

I am using a generic one with no particular history.  USB ID 9710:7830
MosChip Semiconductor MCS7830 Ethernet.  Causes kernel module loads
mcs7830 usbnet mii.

> Also, what does top say during the test? In particular, what are the
> percentages of system (sy), i/o wait (wa) and irq servicing (hi)?

Well, that's interesting.

On XO-1 with os301, sy=3.6, wa=0, hi=5.4, and the iperf process sits at
about 5% CPU utilisation.

On XO-1.5 with os206, sy=58, wa=0, hi=19.3, and the iperf process is
pinned at 99% CPU utilisation.

Given that this is the same 2.6.31 kernel, on different hardware, with
the same binaries ... I'm inclined to suspect there may be a problem
lurking somewhere.

James Cameron

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