dev.bce.X.com_no_buffers increasing and packet loss
davidch at broadcom.com
Tue Mar 9 21:46:20 UTC 2010
> > > patch can fix the RX issue you're suffering from. Anyway,
> would you
> > > give it try the patch at the following URL?
> > > http://people.freebsd.org/~yongari/bce/bce.20100305.diff
> > > The patch was generated against CURRENT and you may see a message
> > > like "Disabling COAL_NOW timedout!" during interface up. You can
> > > ignore that message.
> > It's been running for about 1:23 on the patched driver. I'm still
> > seeing the com_no_buffers increase:
> > [firewall2.jnb1] ~ # sysctl dev.bce |grep com_no_buffers
> > dev.bce.0.com_no_buffers: 5642
> > dev.bce.1.com_no_buffers: 497
> > dev.bce.2.com_no_buffers: 6260612
> > dev.bce.3.com_no_buffers: 4871338
> Still have no idea why these counters are increasing here.
> Actually the counter is read from scratch pad of completion
> processor. The datasheet does not even document the counter.
> Maybe david know better what's happening here(CCed).
> > Interupt rate is down now, at about 3500 per second per interface.
> > Interestingly setting net.inet.ip.fastforwarding=0 reduces CPU
> > consumption from 25% to 9% and less packet loss.
The com_no_buffers statistic comes from firmware and indicates how
many times a valid frame was received but could not be placed into
the receive chain because there were no available RX buffers. The
firmware will then drop the frame but that dropped frame won't be
reflected in any of the hardware based statistics.
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