[PATCH 0/3] ftrace: fix stddev calculation and add a test for it

[Juri Lelli <juri.lelli@gmail.com>]

While profiling kernel functions via ftrace I noticed values of s^2 that
seemed odd. I implemented a test to verify correctness of averages and
s^2 calculations and proved the latter to be wrong. Then I fixed them up.

The first patch refactors function_stat_show() code a bit in order to be
able to implement the test (second patch). Third patch fixes up s^2
calculation (applying Welford's method).

Juri Lelli (3):
  ftrace: refactor basis statistics calculation code
  ftrace: test basic statistics calculation
  ftrace: fix stddev calculation

 kernel/trace/ftrace.c         |   50 ++++++++++++++--------------
 kernel/trace/trace.h          |   16 +++++++++
 kernel/trace/trace_selftest.c |   72 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 114 insertions(+), 24 deletions(-)

-- 
1.7.9.5