[Bridge] Ulog : recvfrom no space available => how do I calculate a good value ?

[Bridge] Ulog : recvfrom no space available => how do I calculate a good value ?

[Jean-Michel Hautbois]

Hi there !

I keep trying to use the ulog/netlink system to receive only the
packets I'm interested by and bridging everything else...
I have a problem using this, because of a too small buffer ?

I am using the recvfrom as the example given on the website, and I am
getting a "no space buffer available" when I have packets  about
2Mbits/sec...
This is very short, as I would like to have >= 100Mbits/sec.

I saw in the manpage an option : --ulog-cprange but I don't understand
how it works...

How can I calculate the range and/or threshold in order to have the
highest rate possible ?

Thanks in advance.
Best Regards,
JM

Re: [Bridge] Ulog : recvfrom no space available => how do I calculate a good value ?

[Saikiran Madugula]

Jean-Michel Hautbois wrote:
> Hi there !
> 
> I keep trying to use the ulog/netlink system to receive only the
> packets I'm interested by and bridging everything else...
> I have a problem using this, because of a too small buffer ?
> 
> I am using the recvfrom as the example given on the website, and I am
> getting a "no space buffer available" when I have packets  about
> 2Mbits/sec...
Probably the netlink receive buffer is being overrun, try increasing the netlink
receive buffer size (see ipulog_create_handle() being called in
libipulog/ulog_test.c for example).

Re: [Bridge] Ulog : recvfrom no space available => how do I calculate a good value ?

[Jean-Michel Hautbois]

2010/1/4 Saikiran Madugula <hummerbliss@gmail.com>:
> Jean-Michel Hautbois wrote:
>> Hi there !
>>
>> I keep trying to use the ulog/netlink system to receive only the
>> packets I'm interested by and bridging everything else...
>> I have a problem using this, because of a too small buffer ?
>>
>> I am using the recvfrom as the example given on the website, and I am
>> getting a "no space buffer available" when I have packets  about
>> 2Mbits/sec...
> Probably the netlink receive buffer is being overrun, try increasing the netlink
> receive buffer size (see ipulog_create_handle() being called in
> libipulog/ulog_test.c for example).

I have a buffer length of 65536 for the socket... It already seems
high for such a low bandwidth...
Or am I misunderstanding something ?

JM

Re: [Bridge] Ulog : recvfrom no space available => how do I calculate a good value ?

[Jean-Michel Hautbois]

Hi everyone !

2010/1/4 Jean-Michel Hautbois <jhautbois@gmail.com>:
> 2010/1/4 Saikiran Madugula <hummerbliss@gmail.com>:
>> Jean-Michel Hautbois wrote:
>>> Hi there !
>>>
>>> I keep trying to use the ulog/netlink system to receive only the
>>> packets I'm interested by and bridging everything else...
>>> I have a problem using this, because of a too small buffer ?
>>>
>>> I am using the recvfrom as the example given on the website, and I am
>>> getting a "no space buffer available" when I have packets  about
>>> 2Mbits/sec...
>> Probably the netlink receive buffer is being overrun, try increasing the netlink
>> receive buffer size (see ipulog_create_handle() being called in
>> libipulog/ulog_test.c for example).
>
> I have a buffer length of 65536 for the socket... It already seems
> high for such a low bandwidth...
> Or am I misunderstanding something ?

I have changed the values in net.core.rmem_max and
net.core.rmem_default to 2097152.
It seems to be better, but when I increase the bandwidth, I have this
error "no buffer space avalaible" again...

Is there any way to have a high performance capture with ebtables+ulog ?
Something like zero-copy mechanism for example...

Thanks in advance !
Best Regards.
JM