ping takes too much

Scott Wood scottwood at
Sat Jan 19 09:48:58 EST 2008

DI BACCO ANTONIO - technolabs wrote:
> I have two different boards: one with MPC875 running at 66 MHz cpu/66 
> MHz bus, one with MPC880 running at 132 MHz cpu /66MHz bus, I load the 
> same kernel and root file system on both the boards that have only 
> different u-boot(s).
> If I do a ping on the MPC875 I get a round trip of 0.300 ms, 
> while on the other one I get 0.900 ms, I expected the opposite.
> Could be an issue with memory configuration? In the formula to calculate 
> the PTx on the MPC885RM manual I used 66 MHz as "system clock" for the 
> first board and 132 MHz for the second board. Probably this is a mistake 
> because "system clock" should be the bus clock but how this can so 
> adversely affect the ping round trip?

Are you sure the timebase clock is what the kernel thinks it is?  Does 
the time-of-day clock progress at the correct rate?


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