On Tue, Sep 13, 2016 at 06:45:01PM +0900, Byungchul Park wrote:

In non-oops case, it's usually not necessary to check all words of stack
area to extract backtrace. Instead, we can achieve it by tracking frame
pointer. So made it possible to save stack trace lightly in normal case.

I measured its ovehead and printed its difference of sched_clock() with
my QEMU x86 machine. The latency was improved over 80% when
trace->max_entries = 5.

Again this code will (probably) be obsolete soon.  And another quote
from my previous review:

  So how about we change save_stack_trace() to use print_context_stack()
  for CONFIG_FRAME_POINTER=n and print_context_stack_bp() for
  CONFIG_FRAME_POINTER=y?  That would preserve the existing behavior, no?

-- 
Josh

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