From: Scott Wood <scottwood@freescale.com>
To: DI BACCO ANTONIO - technolabs <Antonio.DiBacco@technolabs.it>
Cc: linuxppc-embedded@ozlabs.org
Subject: Re: ping 127.0.0.1 takes too much
Date: Fri, 18 Jan 2008 16:48:58 -0600 [thread overview]
Message-ID: <47912CDA.9020603@freescale.com> (raw)
In-Reply-To: <F1F6EC0C8B75034F9E3A79FC85122E8E264A1A@aquib01a>
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 127.0.0.1 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?
-Scott
next prev parent reply other threads:[~2008-01-18 22:48 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-18 22:33 ping 127.0.0.1 takes too much DI BACCO ANTONIO - technolabs
2008-01-18 22:48 ` Scott Wood [this message]
2008-01-18 23:10 ` DI BACCO ANTONIO - technolabs
2008-01-18 23:17 ` Scott Wood
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