Re: [BUG] Strange 1-second pauses during Resume-from-RAM

Ingo Molnar
2007-12-04T09:35:45Z

* Jörn Engel <joern@logfs.org> wrote:

> On Mon, 3 December 2007 01:57:02 +0100, Jörn Engel wrote:
> >
> > After an eternity of compile time, this config does generate some useful
> > output. qemu is not to blame.
>
> Or is it? The output definitely looks suspicious. Large amounts of
> code get processed within a microsecond, while update_wall_time()
> appears to cause huge delays every time it is called:
> http://logfs.org/~joern/trace
>
> Does this output make sense or does it rather indicate some sloppiness
> wrt. time in the qemu virtual machine?

not sure. It could be qemu being scheduled away? You could try to run
qemu with nice -20 or so, to avoid getting preempted. If time lapses
like this still show up:

trace-cm 434 0D.h. 1008us!: do_timer (tick_periodic)
trace-cm 434 0D.h. 1972us+: update_wall_time (do_timer)

trace-cm 434 0D.h. 1008us!: do_timer (tick_periodic)
trace-cm 434 0D.h. 1972us+: update_wall_time (do_timer)

then that could indicate a timekeeping weirdness, OR it could mean that
qemu is simply very slow. (there could be timer hw access between those
two function calls)

Ingo