BeagleBone slow inbound net I/O

Ian Lepore ian at freebsd.org
Sat Mar 14 13:41:03 UTC 2015


On Sat, 2015-03-14 at 03:15 -0400, Brett Wynkoop wrote:
> On Fri, 13 Mar 2015 23:02:25 -0700
> Tim Kientzle <tim at kientzle.com> wrote:
> 
> > 
> > > On Mar 11, 2015, at 1:51 PM, Brett Wynkoop <freebsd-arm at wynn.com>
> > > wrote:
> > > 
> > > Have I managed to find a network driver issue?  Any ideas how to
> > > gather more information to help get to the bottom of things?
> > > 
> > 
> > $ sysctl dev.cpsw
> > 
> > This will dump detailed statistics from the Ethernet hardware and
> > driver.
> > 
> > Tim
> > 
> 
> After a short time while doing nfs i/o
> 
> 
> [wynkoop at beaglebone ~]$ sysctl dev.cpsw | grep -i error
> dev.cpsw.0.stats.RxCrcErrors: 40
> dev.cpsw.0.stats.RxAlignErrors: 32
> dev.cpsw.0.stats.CarrierSenseErrors: 0
[...]
> [wynkoop at beaglebone ~]$ sysctl dev.cpsw | grep -i error
> dev.cpsw.0.stats.RxCrcErrors: 262
> dev.cpsw.0.stats.RxAlignErrors: 231
> dev.cpsw.0.stats.CarrierSenseErrors: 0
> [wynkoop at beaglebone ~]$ 
> 
> So we can see climbing errors.  I am not sure how this compares to the
> results of others. The above was during the first few minutes of a
> buildworld from an nfs share.
> 
> At the same time on the console:
> 
> Mar 14 03:07:47 beaglebone amd[1163]: mountd rpc failed: RPC: Can't
> decode result Mar 14 03:11:48 beaglebone amd[1399]: mountd rpc failed:
> RPC: Can't decode result
> 
> which makes sense with the above errors I think.

On mine:

root at bb:/usr/ports/benchmarks/iperf # sysctl dev.cpsw | grep Err
dev.cpsw.0.stats.RxCrcErrors: 0
dev.cpsw.0.stats.RxAlignErrors: 0
dev.cpsw.0.stats.CarrierSenseErrors: 0

That's after 3 days of uptime including doing builds over nfs, and all
the iperf testing I was doing yesterday (no errors after megabytes of
transfers).

I wonder if your power supply is failing and injecting transient
glitches under heavy load or something?

-- Ian




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