Re: [PATCH] gettimeofday stability
From: Gabriel Paubert <hidden>
Date: 2001-04-12 18:09:16
On Wed, 11 Apr 2001, Karim Yaghmour wrote:
While porting the Linux Trace Toolkit to PPC I noticed a problem that may be explained by the symptoms described. The way it works is that LTT uses do_gettimeofday() to stamp the events that occur. Occasionnaly, a trace would contain entries where the timestamp will jump (from one event to the next) of approximately 4295 seconds. Later on, this would come back to a "normal" value. And the 4295 seconds are 2^32/1000000. Hence the underflow. This has been noticed with both 2.2.x and 2.4.x kernels.
Given that time handling is completely different in 2.2 and 2.4, it is surprising. This would indicate that a decrementer interrupt has happened too early. How often does it happen ? Does it still happen with recent kernels ? Were you running something that touches the decrementer (MOL, RTLINUX) ? Regards, Gabriel ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/