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Date: Wed, 28 Feb 2024 22:32:48 -0800
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Subject: [PATCH v3 2/7] perf trace: Ignore thread hashing in summary
From: Ian Rogers <irogers@google.com>
To: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, 
	Arnaldo Carvalho de Melo <acme@kernel.org>, Namhyung Kim <namhyung@kernel.org>, 
	Mark Rutland <mark.rutland@arm.com>, 
	Alexander Shishkin <alexander.shishkin@linux.intel.com>, Jiri Olsa <jolsa@kernel.org>, 
	Ian Rogers <irogers@google.com>, Adrian Hunter <adrian.hunter@intel.com>, 
	Oliver Upton <oliver.upton@linux.dev>, Yang Jihong <yangjihong1@huawei.com>, 
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
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Commit 91e467bc568f ("perf machine: Use hashtable for machine
threads") made the iteration of thread tids unordered. The perf trace
--summary output sorts and prints each hash bucket, rather than all
threads globally. Change this behavior by turn all threads into a
list, sort the list by number of trace events then by tids, finally
print the list. This also allows the rbtree in threads to be not
accessed outside of machine.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/builtin-trace.c  | 41 +++++++++++++++++++++----------------
 tools/perf/util/rb_resort.h |  5 -----
 2 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 109b8e64fe69..90eaff8c0f6e 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -74,6 +74,7 @@
 #include <linux/err.h>
 #include <linux/filter.h>
 #include <linux/kernel.h>
+#include <linux/list_sort.h>
 #include <linux/random.h>
 #include <linux/stringify.h>
 #include <linux/time64.h>
@@ -4312,34 +4313,38 @@ static unsigned long thread__nr_events(struct thread_trace *ttrace)
 	return ttrace ? ttrace->nr_events : 0;
 }
 
-DEFINE_RESORT_RB(threads,
-		(thread__nr_events(thread__priv(a->thread)) <
-		 thread__nr_events(thread__priv(b->thread))),
-	struct thread *thread;
-)
+static int trace_nr_events_cmp(void *priv __maybe_unused,
+			       const struct list_head *la,
+			       const struct list_head *lb)
 {
-	entry->thread = rb_entry(nd, struct thread_rb_node, rb_node)->thread;
+	struct thread_list *a = list_entry(la, struct thread_list, list);
+	struct thread_list *b = list_entry(lb, struct thread_list, list);
+	unsigned long a_nr_events = thread__nr_events(thread__priv(a->thread));
+	unsigned long b_nr_events = thread__nr_events(thread__priv(b->thread));
+
+	if (a_nr_events != b_nr_events)
+		return a_nr_events < b_nr_events ? -1 : 1;
+
+	/* Identical number of threads, place smaller tids first. */
+	return thread__tid(a->thread) < thread__tid(b->thread)
+		? -1
+		: (thread__tid(a->thread) > thread__tid(b->thread) ? 1 : 0);
 }
 
 static size_t trace__fprintf_thread_summary(struct trace *trace, FILE *fp)
 {
 	size_t printed = trace__fprintf_threads_header(fp);
-	struct rb_node *nd;
-	int i;
-
-	for (i = 0; i < THREADS__TABLE_SIZE; i++) {
-		DECLARE_RESORT_RB_MACHINE_THREADS(threads, trace->host, i);
+	LIST_HEAD(threads);
 
-		if (threads == NULL) {
-			fprintf(fp, "%s", "Error sorting output by nr_events!\n");
-			return 0;
-		}
+	if (machine__thread_list(trace->host, &threads) == 0) {
+		struct thread_list *pos;
 
-		resort_rb__for_each_entry(nd, threads)
-			printed += trace__fprintf_thread(fp, threads_entry->thread, trace);
+		list_sort(NULL, &threads, trace_nr_events_cmp);
 
-		resort_rb__delete(threads);
+		list_for_each_entry(pos, &threads, list)
+			printed += trace__fprintf_thread(fp, pos->thread, trace);
 	}
+	thread_list__delete(&threads);
 	return printed;
 }
 
diff --git a/tools/perf/util/rb_resort.h b/tools/perf/util/rb_resort.h
index 376e86cb4c3c..d927a0d25052 100644
--- a/tools/perf/util/rb_resort.h
+++ b/tools/perf/util/rb_resort.h
@@ -143,9 +143,4 @@ struct __name##_sorted *__name = __name##_sorted__new
 	DECLARE_RESORT_RB(__name)(&__ilist->rblist.entries.rb_root,		\
 				  __ilist->rblist.nr_entries)
 
-/* For 'struct machine->threads' */
-#define DECLARE_RESORT_RB_MACHINE_THREADS(__name, __machine, hash_bucket)    \
- DECLARE_RESORT_RB(__name)(&__machine->threads[hash_bucket].entries.rb_root, \
-			   __machine->threads[hash_bucket].nr)
-
 #endif /* _PERF_RESORT_RB_H_ */
-- 
2.44.0.278.ge034bb2e1d-goog