Hi!
> >>>Wouldn't merging the two approaches be in the interest of conserving
> >>>cpu resources, while at the same time reflecting an accurate view of
> >>>cpu utilization?
> >>
> >>I think that this would be a worthwhile endeavour once/if
> >>sched_clock() is fixed. This is especially the case as CPUs get
> >>faster as many tasks may run to completion in less than a tick.
> >
> >That may not be as simple as it seems. To properly account system v user
> >time using the sched_clock we'd have to hook into arch dependant asm
> >code to know when entering and exiting kernel context. That is far more
> >invasive than the simple on/off runqueue timing we currently do for
> >scheduling accounting.
>
> Yes, it is a problem and we may have to do something approximate like
> counting ticks for sys time and subtracting that from the total to get
> user time when reporting the times to user space (only a bit more
> complex to make sure we don't end up with negative times).
Yes, please.
> How is it intended to handle this problem in the tickless kernel?
Even our "tickless" kernels do tick while CPU is busy.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
