perf tools: struct thread has a tid not a pid

As evident from 'machine__process_fork_event()' and
'machine__process_exit_event()' the 'pid' member of struct thread is
actually the tid.

Rename 'pid' to 'tid' in struct thread accordingly.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1372944040-32690-13-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index 313a5a7..8deee19 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -55,14 +55,14 @@
 static int64_t
 sort__thread_cmp(struct hist_entry *left, struct hist_entry *right)
 {
-	return right->thread->pid - left->thread->pid;
+	return right->thread->tid - left->thread->tid;
 }
 
 static int hist_entry__thread_snprintf(struct hist_entry *self, char *bf,
 				       size_t size, unsigned int width)
 {
 	return repsep_snprintf(bf, size, "%*s:%5d", width - 6,
-			      self->thread->comm ?: "", self->thread->pid);
+			      self->thread->comm ?: "", self->thread->tid);
 }
 
 struct sort_entry sort_thread = {
@@ -77,7 +77,7 @@
 static int64_t
 sort__comm_cmp(struct hist_entry *left, struct hist_entry *right)
 {
-	return right->thread->pid - left->thread->pid;
+	return right->thread->tid - left->thread->tid;
 }
 
 static int64_t