On Monday 12 February 2007 16:55, Stephen Rothwell wrote: > On Mon, 12 Feb 2007 16:44:22 +1100 "Con Kolivas" <[EMAIL PROTECTED]> wrote: > > The kernel looks at what is using cpu _only_ during the timer > > interrupt. Which means if your HZ is 1000 it looks at what is running > > at precisely the moment those 1000 timer ticks occur. It is > > theoretically possible using this measurement system to use >99% cpu > > and record 0 usage if you time your cpu usage properly. It gets even > > more inaccurate at lower HZ values for the same reason. > > That is not true on all architecures, some do more accurate accounting by > recording the times at user/kernel/interrupt transitions ...
Indeed. It's certainly the way the common more boring pc architectures do it though. -- -ck - 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/
