From: Hitoshi Mitake Date: Wed, 21 Apr 2010 12:23:54 +0000 (+0900) Subject: perf lock: Fix state machine to recognize lock sequence X-Git-Tag: v2.6.35-rc1~522^2~94 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e4cef1f65061429c3e8b356233e87dc6653a9da5;p=pandora-kernel.git perf lock: Fix state machine to recognize lock sequence Previous state machine of perf lock was really broken. This patch improves it a little. This patch prepares the list of state machine that represents lock sequences for each threads. These state machines can be one of these sequences: 1) acquire -> acquired -> release 2) acquire -> contended -> acquired -> release 3) acquire (w/ try) -> release 4) acquire (w/ read) -> release The case of 4) is a little special. Double acquire of read lock is allowed, so the state machine counts read lock number, and permits double acquire and release. But, things are not so simple. Something in my model is still wrong. I counted the number of lock instances with bad sequence, and ratio is like this (case of tracing whoami): bad:233, total:2279 version 2: * threads are now identified with tid, not pid * prepared SEQ_STATE_READ_ACQUIRED for read lock. * bunch of struct lock_seq_stat is now linked list * debug information enhanced (this have to be removed someday) e.g. | === output for debug=== | | bad:233, total:2279 | bad rate:0.000000 | histogram of events caused bad sequence | acquire: 165 | acquired: 0 | contended: 0 | release: 68 Signed-off-by: Hitoshi Mitake Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Jens Axboe Cc: Jason Baron Cc: Xiao Guangrong Cc: Ingo Molnar LKML-Reference: <1271852634-9351-1-git-send-email-mitake@dcl.info.waseda.ac.jp> [rename SEQ_STATE_UNINITED to SEQ_STATE_UNINITIALIZED] Signed-off-by: Frederic Weisbecker --- Reading git-diff-tree failed