Re: Continual reading from the PowerPc time base register is not stable
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2010-03-25 08:21:58
On Thu, 2010-03-25 at 10:41 +0800, Csdncannon wrote:
In my program, the value of the 64-bit time base register is
read out, and you will find the later value is even smaller than the
earlier value from the log “log_timebase”. While the kernel depends on
the accuracy of the timebase for the compensation of the lost PIT
interrupt, the negative value between two continual timebase reading
will bring to the jump of the jiffies. And this timebase problem will
bring to the instability of the gettimeofday system call.
Do you have any idea about this problem, thanks for your any
advice. Attached is the code and log.This is a concern, it should definitely not happen. What machine is that ? is the code compiled 32-bit or 64-bit ? What kernel version ? Arnd, any chance that could relate to the bug you've been chasing on Cell ? Cheers, Ben.
Thanks Gino _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev