TODO.txt

To Do
=====
*Add support for other counters to be in Counter mode. 
*Currently, backtracing of the stack will terminate if the stack crosses
 a page boundary and a page fault must occur. A page fault cannot occur
 while servicing a performance monitor interrupt. A work around is to 
 disable PMIs, and unwind the stack only when interrupts are re-enabled. 
*For x86_64, CONFIG_DEBUG_INFO and CONFIG_FRAME_POINTER must be turned
 on and the kernel recompiled for backtracing to work correctly.
 CONFIG_DEBUG_INFO is required for backtracing to work in user space.
 CONFIG_FRAME_POINTER is required for backtracing in kernel space. 
 It may be possible to work around this limitation through hackery as
 noted below.
 -> Verify that opensuse has CONFIG_DEBUG_INFO turned on else 
    can't view callstacks with suse linux. 
 
Notes
=====
*The time between timer interrupts cannot be changed, i.e. there is no
 mechanism to register a callback from the decrementer after a 
 specified time? Refer to arch/ppc64/kernel/time.c:timer_interrupt().
 The only work around is to hack the kernel. 
*With reference to collecting a backtrace without CONFIG_DEBUG_INFO set
 in the kernel. It may be possible to unroll the interrupt stack to 
 obtain %rbp at the time of the interrupt.