Hi Michael,
Thanks for the detailed reply.
I think I have exactly the same problem that you have - the networking
stops working.
I got the LwIP stats after the networking stopped working, see
LINK
xmit: 0
rexmit: 0
recv: 0
fw: 0
drop: 0
chkerr: 0
lenerr: 0
memerr: 0
rterr: 0
proterr: 0
opterr: 0
err: 0
cachehit: 0
IP_FRAG
xmit: 0
rexmit: 0
recv: 0
fw: 0
drop: 0
chkerr: 0
lenerr: 0
memerr: 0
rterr: 0
proterr: 0
opterr: 0
err: 0
cachehit: 0
IP
xmit: 17643
rexmit: 0
recv: 63100
fw: 0
drop: 0
chkerr: 0
lenerr: 0
memerr: 0
rterr: 0
proterr: 0
opterr: 0
err: 0
cachehit: 0
ICMP
xmit: 2775
rexmit: 0
recv: 2950
fw: 0
drop: 175
chkerr: 0
lenerr: 0
memerr: 0
rterr: 0
proterr: 175
opterr: 0
err: 0
cachehit: 0
UDP
xmit: 4714
rexmit: 0
recv: 53209
fw: 0
drop: 0
chkerr: 0
lenerr: 0
memerr: 0
rterr: 0
proterr: 0
opterr: 0
err: 0
cachehit: 0
TCP
xmit: 6715
rexmit: 0
recv: 6941
fw: 0
drop: 0
chkerr: 0
lenerr: 0
memerr: 2705
rterr: 0
proterr: 0
opterr: 0
err: 0
cachehit: 0
PBUF - "each pbuf is 1024 bytes"
avail: 30
used: 1
max: 11
err: 2
alloc_locked: 0
refresh_locked: 0
MEM HEAP
avail: 1024
used: 0
max: 720
err: 0
MEM PBUF
avail: 8
used: 0
max: 2
err: 0
MEM RAW_PCB
avail: 4
used: 0
max: 0
err: 0
MEM UDP_PCB
avail: 3
used: 3
max: 3
err: 0
MEM TCP_PCB
avail: 16
used: 0
max: 8
err: 0
MEM TCP_PCB_LISTEN
avail: 1
used: 1
max: 1
err: 0
MEM TCP_SEG
avail: 6
used: 0
max: 4
err: 0
MEM NETBUF
avail: 10
used: 0
max: 6
err: 0
MEM NETCONN
avail: 12
used: 4
max: 7
err: 0
MEM API_MSG
avail: 6
used: 0
max: 2
err: 0
MEM TCP_MSG
avail: 12
used: 0
max: 7
err: 0
MEM TIMEOUT
avail: 4
used: 2
max: 3
err: 0
I would appreciate if can take a look
Elad
On Wed, Jun 13, 2012 at 6:47 PM, Michael O'Dowd
<michael.odowd@kuantic.com> wrote:
Hi Elad,
I ran into a similar problem recently. I'm using a recent CVS checkout
rather than 3.0. Also, I'm probably not using the same ethernet HW, so I
don't know how well my reply corresponds to your case.
The eth_drv.c file is the glue between lwIP and the underlying ethernet
driver, so the issue that you are encountering may be specific to the
driver. In my case, when under stress, eth_drv.c generates the error
message: "cannot allocate pbuf to receive packet". Soon after that, the
ethernet driver stops receiving traffic permanently, but does not crash. In
your case, if I understand correctly, your system crashes.
The issue is that when eth_drv_recv() fails to allocate a pbuf, it returns
without calling the ethernet driver recv() function: (sc->funs->recv)(). In
my case, the driver requires that it's recv() function be called, in order
to complete the processing of the packet reception and to free up the
receive buffer(s). Failing to call it, apparently causes the receive path to
cease functioning (I'm still investigating the details). In your case, I
gather that it crashes the system.
Note: I'm running on an NXP 1788 (Cortex-M3), using the
"devs/arm/lpc2xxx/current/src/if_lpc2xxx.c" ethernet driver.
There are two aspects to this problem:
1) In my opinion, there is a bug in eth_drv_recv(). If there are no pbufs
available, then it should at least cause the received packet to be
discarded. Otherwise, the system may fail whenever there is a minor burst of
traffic on the network. It doesn't take much: there are only 16 pbufs
available by default. Whether or not the system fails, depends on how the
ethernet driver reacts to the failure to call it's recv() function. I hope
to fix this on my platform in the near future.
2) You should also keep an eye on your pbuf usage, just to make sure that
you don't have a pbuf memroy leak. You could also try to allocate more
pbufs, if you have the available memory.
If you are using the default lwip configuration, the pbuf memory allocation
is handled by memp.[hc]. It has a fixed number of pbufs available. The
default is 16 pbufs, and can be changed in the configtool under: [lwIP
networking stack/Memory options/Number of memp struct pbufs].
Alternatively, if you have lots of memory, you could enable the checkbox:
[lwIP networking stack/Memory options/Use malloc for pool allocations]. This
bypasses the memp pools and their static limitations. Though this will make
it harder to spot a pbuf memory leak. I haven't tried this personally.
Finally, (when using memp) the pbuf usage can be monitored with
lwip/stats.h. If you have access to a serial port, try calling
stats_display(). Here is a snippet of the pbuf related output:
MEM PBUF_POOL
avail: 16
used: 0
max: 3
err: 0
The "err" counter increases when pbuf_alloc() fails.
Hope that helps,
Regards,
Michael O'Dowd
Kuantic SAS
On 12/06/2012 22:40, Elad Yosef wrote:
Hi all,
I'm using LwIP stack on my target and experiencing crashes under stress.
function eth_drv_recv) from ../io/eth/v3_0/ser/lwip/eth_drv.c
calls pbuf_alloc() and this allocation fails.
Is this result of some bad configuration?
Thanks
Elad