diff options
| author | Juri Lelli <[email protected]> | 2013-06-12 12:03:18 +0200 |
|---|---|---|
| committer | Steven Rostedt <[email protected]> | 2013-06-19 23:32:09 -0400 |
| commit | 52d85d763086594f139bf7d3a5641abeb91d9f57 (patch) | |
| tree | ef1e85c2ac60076ecc3a31a60391653acff97e0b /tools/perf/scripts/python/syscall-counts.py | |
| parent | 195a84d91e92ee3fe571a2086a6db7e17bf5bc7c (diff) | |
ftrace: Fix stddev calculation in function profiler
When FUNCTION_GRAPH_TRACER is enabled, ftrace can profile kernel functions
and print basic statistics about them. Unfortunately, running stddev
calculation is wrong. This patch corrects it implementing Welford’s method:
s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2) .
Link: http://lkml.kernel.org/r/[email protected]
Cc: Frederic Weisbecker <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Juri Lelli <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
Diffstat (limited to 'tools/perf/scripts/python/syscall-counts.py')
0 files changed, 0 insertions, 0 deletions