>Synopsis: absurd packet loss for some packet sizes on Beaglebone Black
>Category: armv7
>Environment:
System : OpenBSD 5.4
Details : OpenBSD 5.4-current (GENERIC-OMAP) #11: Tue Oct 8
08:49:25 CEST 2013
r...@imx.fritz.box:/usr/src/sys/arch/armv7/compile/GENERIC-OMAP
Architecture: OpenBSD.armv7
Machine : armv7
>Description:
For some outgoing ping packet sizes, almost but not complete packet
loss is seen.
Others, just some packet loss is seen.
-s225 : almost complete packet loss.
-s224, -s226 : no packet loss seen.
-s289 : high packet loss.
-s480 : one packet loss.
Repeatable on multiple snapshot kernels and two BBB systems.
>How-To-Repeat:
# ping -f -n -c100 -s289 thecus
PING thecus.in.nickh.org (192.168.1.165): 289 data bytes
........................................................................................................
--- thecus.in.nickh.org ping statistics ---
214 packets transmitted, 100 packets received, 53.3% packet loss
round-trip min/avg/max/std-dev = 1.587/2.734/5.585/0.807 ms
# ping -qf -n -c100 -s289 thecus
PING thecus.in.nickh.org (192.168.1.165): 289 data bytes
--- thecus.in.nickh.org ping statistics ---
102 packets transmitted, 100 packets received, 2.0% packet loss
round-trip min/avg/max/std-dev = 1.678/1.898/6.286/0.598 ms
[ -q makes a HUGE difference!!! ]
# ping -f -n -c100 -s225 thecus
PING thecus.in.nickh.org (192.168.1.165): 225 data bytes
[well, let's just say it hasn't returned yet. with -c10, it
took over 8000 packets to get ten responses. Finally gave up at:]
--- thecus.in.nickh.org ping statistics ---
21147 packets transmitted, 19 packets received, 99.9% packet loss
round-trip min/avg/max/std-dev = 1.770/1.814/2.167/0.103 ms
[ -q doesn't seem to make as much difference here ]
maybe related, maybe not. might just be a crappy switch, but really odd:
# ping -f -n -c100 -s480 thecus
PING thecus.in.nickh.org (192.168.1.165): 480 data bytes
--- thecus.in.nickh.org ping statistics ---
100 packets transmitted, 100 packets received, 0.0% packet loss
round-trip min/avg/max/std-dev = 1.739/2.612/6.012/0.731 ms
# ping -f -n -c100 -s480 thecus
PING thecus.in.nickh.org (192.168.1.165): 480 data bytes
--- thecus.in.nickh.org ping statistics ---
101 packets transmitted, 100 packets received, 1.0% packet loss
round-trip min/avg/max/std-dev = 1.740/5.135/11.687/3.091 ms
-s480 loses one packet, somewhere around 20-50% of the time,
for -n10 to -n1000. Haven't seen lose two packets for anything in
that range. -s10 never loses a packet, -s1000 never loses a packet.
Lots of things in the -s480 neighborhood lose ONE packet sometimes.
>Fix:
got me!
dmesg:
OpenBSD 5.4-current (GENERIC-OMAP) #11: Tue Oct 8 08:49:25 CEST 2013
r...@imx.fritz.box:/usr/src/sys/arch/armv7/compile/GENERIC-OMAP
real mem = 536870912 (512MB)
avail mem = 519208960 (495MB)
mainbus0 at root
cpu0 at mainbus0: ARM Cortex A8 R3 rev 2 (ARMv7 core)
cpu0: DC enabled IC enabled WB disabled EABT branch prediction enabled
cpu0: 32KB(64b/l,4way) I-cache, 32KB(64b/l,4way) wr-back D-cache
omap0 at mainbus0: BeagleBone
prcm0 at omap0 rev 0.2
sitaracm0 at omap0: control module, rev 1.0
intc0 at omap0 rev 5.0
omap0: device edma unit 0 not configured
dmtimer0 at omap0 rev 3.1
dmtimer1 at omap0 rev 3.1
omdog0 at omap0 rev 0.1
ommmc0 at omap0
sdmmc0 at ommmc0
ommmc1 at omap0
sdmmc1 at ommmc1
com0 at omap0: ti16750, 64 byte fifo
com0: console
cpsw0 at omap0: version 1.12 (0), address c8:a0:30:ad:c7:fe
ukphy0 at cpsw0 phy 0: Generic IEEE 802.3u media interface, rev. 1: OUI
0x0001f0, model 0x000f
/dev/ksyms: Symbol table not valid.
scsibus0 at sdmmc0: 2 targets, initiator 0
sd0 at scsibus0 targ 1 lun 0: <SD/MMC, Drive #01, > SCSI2 0/direct fixed
sd0: 14991MB, 512 bytes/sector, 30702592 sectors
scsibus1 at sdmmc1: 2 targets, initiator 0
sd1 at scsibus1 targ 1 lun 0: <SD/MMC, Drive #01, > SCSI2 0/direct fixed
sd1: 1832MB, 512 bytes/sector, 3751936 sectors
vscsi0 at root
scsibus2 at vscsi0: 256 targets
softraid0 at root
scsibus3 at softraid0: 256 targets
boot device: sd0
root on sd0a (3570732e182a601e.a) swap on sd0b dump on sd0b
WARNING: CHECK AND RESET THE DATE!
usbdevs:
usbdevs: no USB controllers found
pcidump:
acpidump:
