On Sun, 8 Jun 2008, Luke -Jr wrote:
> On Sunday 08 June 2008, Maciej W. Rozycki wrote:
> > On Sun, 8 Jun 2008, Luke -Jr wrote:
> > > > Not exactly. Try harder -- this is simple arithmetic and you've got
> > > > all the data given above already. :)
> > >
> > > 200 / 2? I'm not really sure what a 'jiffy' is..
> >
> > Hmm, I have thought it can be inferred from the code involved or failing
> > that -- Google... Well, anyway, a jiffy is a tick of the kernel timer or,
> > specifically in this context and to be more precise, the interval between
> > such two consecutive ticks or, in other words, 1/HZ.
^^
Look at CONFIG_HZ, which is probably 100, 250, or 1000.
> jiffy = 1 / 200000 HZ = 0.000005 sec/tick
> loop = 200000 instructions / 2 instructions per loop = 100000 loops/sec
>
> So 0.00000000005 loops per jiffy? But it can't be, since loops_per_jiffy isn't
> floating point... :/
So loops_per_jiffie is approx. CPU clock frequency / CONFIG_HZ.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
