ring_buffer: compressed event header
authorLai Jiangshan <laijs@cn.fujitsu.com>
Fri, 24 Apr 2009 03:27:05 +0000 (11:27 +0800)
committerSteven Rostedt <rostedt@goodmis.org>
Fri, 24 Apr 2009 04:08:38 +0000 (00:08 -0400)
commit334d4169a6592d3fcd863bbe822a8f6985ffa9af
tree3ac9c038304eaa69b06d9cac735fd62a8d6c47b3
parentc2518c4366f087ebc10b3919cb2461bbe4f42d0c
ring_buffer: compressed event header

RB_MAX_SMALL_DATA = 28bytes is too small for most tracers, it wastes
an 'u32' to save the actually length for events which data size > 28.

This fix uses compressed event header and enlarges RB_MAX_SMALL_DATA.

[ Impact: saves about 0%-12.5%(depends on tracer) memory in ring_buffer ]

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <49F13189.3090000@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
include/linux/ring_buffer.h
kernel/trace/ring_buffer.c