candump app will lost rx packets while it prints the received data frames

candump app will lost rx packets while it prints the received data frames

[xuewentian]

Hi all,

  I wonder that when the can select/poll bug can be fixed ? What reason 
has it not been fixed yet? Thanks a lot.

 and now I encounter another problem, I use a sufficient delay for cansend 
on the first borad, and anther board using candump to
receive the data frame.

board 1:
cansend can0  -l 500 -i 0x123 0x11 0x22 0x33 0x44 0x55 0x66 0x77 
0x88   //cansend I have added the delay,and no any write failaure report

board 2:
candump can0    // on the serial terminal, I have only received about 434
                // data frames which are printed on the serial
                // terminal,and no any read error information

and use "ifconfig can0" on the two boards, I found that board 1 has 
increased 500 "TX packets",and board 2 has also increased 500 "RX 
packets", but candump app seemed that lost some packets. what reason is 
it??

Thanks a lot.

Re: candump app will lost rx packets while it prints the received data frames

[Marc Kleine-Budde]

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On 08/28/2013 11:17 AM, xuewentian wrote:
> Hi all,
> 
>   I wonder that when the can select/poll bug can be fixed ? What reason 
> has it not been fixed yet? Thanks a lot.
> 
>  and now I encounter another problem, I use a sufficient delay for cansend 
> on the first borad, and anther board using candump to
> receive the data frame.
> 
> board 1:
> cansend can0  -l 500 -i 0x123 0x11 0x22 0x33 0x44 0x55 0x66 0x77 
> 0x88   //cansend I have added the delay,and no any write failaure report
> 
> board 2:
> candump can0    // on the serial terminal, I have only received about 434
>                 // data frames which are printed on the serial
>                 // terminal,and no any read error information
> 
> and use "ifconfig can0" on the two boards, I found that board 1 has 
> increased 500 "TX packets",and board 2 has also increased 500 "RX 
> packets", but candump app seemed that lost some packets. what reason is 
> it??

Don't print on a serial line what you have received over CAN. Your
serial port is slower than CAN, the socket buffer between kernel and
application will be full sooner or less, then the kernel drops frames.

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
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