perf tools: Add perf trace

This adds perf trace into the set of perf tools.

It is written to fetch the tracepoint samples from perf events
and display them, according to the events information given by
the debugfs files through the util/trace* tools.

It is a rough first shot and doesn't yet handle the cpu,
timestamps fields and some other things.

Example:

 perf record -f -e workqueue:workqueue_execution:record -F 1 -a
 perf trace

       kblockd/0-236   [000]     0.000000: workqueue_execution: thread=:236 func=cfq_kick_queue+0x0
     kondemand/0-360   [000]     0.000000: workqueue_execution: thread=:360 func=do_dbs_timer+0x0
     kondemand/0-360   [000]     0.000000: workqueue_execution: thread=:360 func=do_dbs_timer+0x0
     kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
     kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
     kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
     kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
     kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
     kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
     kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
     kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
     kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
     kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
     kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
     kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0
     kondemand/1-361   [000]     0.000000: workqueue_execution: thread=:361 func=do_dbs_timer+0x0

Todo:

- A lot of things!

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: "Luis Claudio R. Goncalves" <lclaudio@uudg.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Jon Masters <jonathan@jonmasters.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Zhaolei <zhaolei@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Anton Blanchard <anton@samba.org>
LKML-Reference: <1250518688-7207-4-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>