Re: [Xenomai-core] Unwanted mode switch.
On Thu, 2007-01-11 at 16:24 +0100, Gilles Chanteperdrix wrote: > Hi, > > in order to test the nocow patch, I wrote the attached test. Despite the > fact that there is no longer any page fault (I have nucleus debugging > on, so I would get a message if there was a fault), there is still an > unwanted mode switch at step 5. Any idea what could be the cause ? > I'll have a look asap. > > ___ > Xenomai-core mailing list > Xenomai-core@gna.org > https://mail.gna.org/listinfo/xenomai-core -- Philippe. ___ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
Re: [Xenomai-core] Unwanted mode switch.
On Thu, 2007-01-11 at 16:36 +0100, Gilles Chanteperdrix wrote: > Gilles Chanteperdrix wrote: > > Hi, > > > > in order to test the nocow patch, I wrote the attached test. Despite the > > fact that there is no longer any page fault (I have nucleus debugging > > on, so I would get a message if there was a fault), there is still an > > unwanted mode switch at step 5. Any idea what could be the cause ? > > I added a show_stack(NULL, NULL) in xnshadow_relax, and I get the > following stack trace: > xnshadow_relax > hisyscall_event ^^^ Eeek... Which would mean that we would somehow be running the hi-stage handler for a task on behalf of, say, xnshadow_harden()? Could you confirm the backtrace? Any chance the frame unwinding went south here? Dumping the muxid/muxop pair for the hisyscall_event call which attempts to relax the underlying task might be interesting. > xnshadow_sys_migrate > losyscall_event > -- Philippe. ___ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
Re: [Xenomai-core] Unwanted mode switch.
Gilles Chanteperdrix wrote: > Hi, > > in order to test the nocow patch, I wrote the attached test. Despite the > fact that there is no longer any page fault (I have nucleus debugging > on, so I would get a message if there was a fault), there is still an > unwanted mode switch at step 5. Any idea what could be the cause ? I added a show_stack(NULL, NULL) in xnshadow_relax, and I get the following stack trace: xnshadow_relax hisyscall_event xnshadow_sys_migrate losyscall_event -- Gilles Chanteperdrix ___ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
Re: [Xenomai-core] Unwanted mode switch.
Gilles Chanteperdrix wrote: > Hi, > > in order to test the nocow patch, I wrote the attached test. Despite the > fact that there is no longer any page fault (I have nucleus debugging > on, so I would get a message if there was a fault), there is still an > unwanted mode switch at step 5. Any idea what could be the cause ? > Put in some xntrace_user_freeze(0) before or after the point-of-interest in the program, switch on the tracer, and check ipipe/trace/frozen (with appropriate back_trace_points or post_trace_points) what is going on. Once you know the particular code path, instrumenting it can also be done this way: xntrace_special(some_id, some_value_of_interest). Jan signature.asc Description: OpenPGP digital signature ___ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
