Re: Idle picture for those interested.

David Brownell
2008-04-04T22:05:56Z

> > I've not calibrated to verify but that seems to be what the picture is
> > showing so there is some chance the time base is off. All the
> > instruction
> > trace is there to walk it if necessary. There have been some comments
> > about NO_HZ adding some overhead from those who measure MHz around
> > here for things like MP3 load models. I hadn't looked very closely.
>
> One question might be is if the timekeeping could be deferred until
> after you have serviced the IRQ. Is there a reason to make the ISR wait
> for housekeeping?

If the system is in NO_HZ mode, the "jiffies" value could be invalid.
Some IRQ handlers need it to be valid.

- Dave