<p><br>
On Mar 9, 2012 11:57 PM, "Mulyadi Santosa" <<a href="mailto:mulyadi.santosa@gmail.com">mulyadi.santosa@gmail.com</a>> wrote:<br>
><br>
> Hi :)<br>
><br>
> On Fri, Mar 9, 2012 at 18:39, Daniel Hilst <<a href="mailto:danielhilst@gmail.com">danielhilst@gmail.com</a>> wrote:<br>
> > The processes that appear in top with brackets are the kernel threads?<br>
><br>
> Yup :)<br>
><br>
> > If so, this threads spend all its time on system mode, right?<br>
><br>
> Yes, it supposed to ...<br>
><br>
> >By the<br>
> > system mode I mean the %sy on top header, since kernel threads hasn't<br>
> > any memory mapped to user space, it can't run on user space at any time,<br>
> > right?<br>
><br>
> IIRC, kernel thread simply "borrow" any previous scheduled task's<br>
> address space. In that matter, it also has user address space. So, if<br>
> wanted, kernel thread could access user space. But normally it doesn't<br>
> do it.<br>
><br>
AFAIK kernel threads do not have any userspace context. As it is never gaurnted which userspace process was previously running when kernel thread scheduled to run.</p>
<p>> ><br>
> ><br>
> > So the total of system mode usage is the sum of all processes processing<br>
> > in kernel space, plus the kernel threads processing, right?<br>
><br>
> remember that kernel threads are also processes, so no need to<br>
> differentiate between normal processes and kernel threads, especially<br>
> when we talk about CPU utilization.<br>
><br>
> --<br>
> regards,<br>
><br>
> Mulyadi Santosa<br>
> Freelance Linux trainer and consultant<br>
><br>
> blog: <a href="http://the-hydra.blogspot.com">the-hydra.blogspot.com</a><br>
> training: <a href="http://mulyaditraining.blogspot.com">mulyaditraining.blogspot.com</a><br>
><br>
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