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Re: space query
- From: Jim Keniston <jkenisto at linux dot vnet dot ibm dot com>
- To: sscheider <sscheider at aptxion dot com>
- Cc: systemtap at sourceware dot org
- Date: Mon, 12 Mar 2012 11:22:53 -0700
- Subject: Re: space query
- References: <33482258.post@talk.nabble.com>
On Sun, 2012-03-11 at 12:09 -0700, sscheider wrote:
> Howdy! I am wondering if systemtap probes run in kernel or user space.
For both kernel probes and user-space probes, the probe handlers (i.e.,
what you specify in your stap script) run in kernel space.
However, in probes of user-space code, the probe-handling sequence may
(i.e., if the probed instruction isn't emulated) include single-stepping
a copy of the probed instruction in user space.
> In
> either case, do the probes contribute to the "run" state duration of a given
> PID?
For both kernel and user-space probes, the handler runs in the context
of the process that hit the probepoint.
> If so, which? I'm using schedtimes.stp.
> Thanks!
Jim Keniston
IBM Linux Technology Center