Re: C_CAN: can frame drops

[Marc Kleine-Budde <mkl@pengutronix.de>]

[-- Attachment #1: Type: text/plain, Size: 1545 bytes --]

On 07/25/2014 11:47 AM, Ssagarr Patil wrote:
>>> Any suggestion on how to still improve the performance so as there is zero frame loss ?
>>> either on driver or application side.
>>
>> Use the latest kernel, at least v3.15 which has tglx's patches
>> integrated. v3.16 might even be better. If you want to log all CAN
>> messages, you can probably make use of recvmmsg() to receive more than
>> one CAN frame at a time (instead of using recvmsg() or read()). When
>> writing to disk, don't write a single CAN frame at a time, it's better
>> to write large blocks, i.e. several 4k of data.
>>
> I am using the v3.16 (the master branch from git://gitorious.org/linux-can/linux-can.git)
> 
> OK will try experiment with recvmmsg() & and writing to disk with large blocks.
>  
>> Depending on the actual c_can/d_can implementation you're using, there
>> might be some optimisation left in the driver, i.e. use 32 bit access if
>> possible. However before touching the driver, measurement to identify
>> the hot spots should be done.
>>
> OK
> 
>> The next step would be to switch to preempt rt enabled system.
>>
> I am afraid I cant use this, as project needs to be run on normal Linux.

Preempt-rt is a normal Linux system, though. :)

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 242 bytes --]