Re: [Ocera-development] [Socketcan-users] Socketcan and LinCAN benchmarks

[Oliver H. <soc...@ha...>]

Michal Sojka wrote:
> On Wednesday 02 of September 2009 18:37:26 Oliver Hartkopp wrote:
>> Michal Sojka wrote:
>>> The testbed was a Pentium 4 box with a Kvaser quad-head PCI card
>>> (SJA1000 based). We have simply connected output 1 to output 2 and
>>> measured the time how long it takes for the message to go forth and
>>> back.
>> The idea behind my setup was to benchmark the chardev vs netdev in general.
>> For that reason, i used a PEAK PCMCIA card (which had an exclusive IRQ
>> line) and compiled the same driver with and without netdev support:
>>
>> [...]
>>
>> Finally the RX path was faster with netdev and the impact of different
>> driver implementations or the performance of the drivers TX-handling on the
>> SJA1000 was excluded in this benchmark.
> 
> Interesting. We may try to do similar test to check whether the problem is in 
> PEAK's FIFOs or it is a general property (Lincan is also based on FIFOs filled 
> from IRQ).


If you're planning some more tests, i would be interested what happens if you
make the rtt-virtual tests with waits of 0/1/2 ms.

When there is a delay between the sent frames, we probably see a completely
different behaviour on the virtual CANs.


>>> We have used canping [1] tool to generate CAN traffic.
>> I tried to figure out how canping was used with SocketCAN in your testbed.
>> But i didn't find any socket() call :-)
> 
> In http://rtime.felk.cvut.cz/gitweb/canping.git/blob/HEAD:/src/vca_canping.c, 
> you can see vca_open_handle() and other vca_*() functions, which are 
> implemented in libVCA. For socketcan it is in 
> http://ocera.cvs.sourceforge.net/viewvc/ocera/ocera/components/comm/can/canvca/libvca/vca_isocketcan.c?revision=1.4&view=markup

Ah, ok.

Regards,
Oliver