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<p>Hi Benjamin and Olaf,<br>
<br>
Thanks for the suggestions.<br>
<br>
Ideally, what I'm looking for is something that mimics the operation of MASKABLE_EXCEPTION_PSERIES.<br>
I've been looking at the kernel code (entry_64.S, exception.h, head_64.S) but am finding it quite complicated and hard to follow, particularly in the area of interrupt disabling wrt the soft and hard disable logic.<br>
<br>
My initial thought is to do something like this in the beginning of my perfmon2 interrupt handler:<br>
<br>
<tt>void perfmon_pmu_int_handler(struct pt_regs *regs) {</tt><br>
<br>
<tt> if (get_paca()->soft_enabled == 0) {</tt><br>
<tt> /* disable hardware interrupts */</tt><br>
<tt> get_paca()->hard_enabled = 0;</tt><br>
<tt> regs->msr &= ^MSR_EE;</tt><br>
<tt> return;</tt><br>
<tt> }</tt><br>
<tt>...</tt><br>
<tt>}</tt><br>
<br>
Does this seem like it might work?<br>
<br>
Thanks<br>
<br>
Corey Ashford<br>
Software Engineer<br>
IBM Linux Technology Center, Linux Toolchain<br>
Beaverton, OR <br>
503-578-3507 <br>
cjashfor@us.ibm.com<br>
<br>
<br>
<tt>Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote on 05/14/2008 11:46:07 PM:<br>
<br>
> <br>
> On Tue, 2008-05-13 at 15:26 -0700, Corey Ashford wrote:<br>
> > The perfmon2 code is available here: <br>
> > <a href="http://sourceforge.net/project/showfiles.php?group_id=144822">http://sourceforge.net/project/showfiles.php?group_id=144822</a><br>
> > <br>
> > perfmon2's interrupt handler does have a single entry point. Could I <br>
> > somehow mimic what the MASKABLE_EXCEPTION_PSERIES macro does inside<br>
> > of <br>
> > the perfmon2 interrupt handler? Are there examples of this I can look<br>
> > at?<br>
> > <br>
> > That would give us the best of both worlds.<br>
> <br>
> You can definitely snapshot as many data as you can, and if interrupts<br>
> are soft-disabled, just return to the caller, storing that snapshot in<br>
> some per-cpu data structure.<br>
> <br>
> You can then add something to local_irq_restore() that checks whether<br>
> some perfmon2 stuff happened and does the actual storing of the data<br>
> that were previously collected.<br>
> <br>
> Cheers,<br>
> Ben.<br>
> <br>
> <br>
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