Re: [PATCH v3 02/15] x86/dumpstack: Add save_stack_trace()_fast()

[Josh Poimboeuf]

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