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Date:   Tue, 24 Oct 2023 15:23:49 -0700
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Subject: [PATCH v3 46/50] 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>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Nick Terrell <terrelln@fb.com>,
        Kan Liang <kan.liang@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>, Leo Yan <leo.yan@linaro.org>,
        Song Liu <song@kernel.org>,
        Sandipan Das <sandipan.das@amd.com>,
        James Clark <james.clark@arm.com>,
        Anshuman Khandual <anshuman.khandual@arm.com>,
        Miguel Ojeda <ojeda@kernel.org>,
        Liam Howlett <liam.howlett@oracle.com>,
        Yang Jihong <yangjihong1@huawei.com>,
        Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
        Kajol Jain <kjain@linux.ibm.com>,
        K Prateek Nayak <kprateek.nayak@amd.com>,
        Sean Christopherson <seanjc@google.com>,
        Yanteng Si <siyanteng@loongson.cn>,
        Ravi Bangoria <ravi.bangoria@amd.com>,
        German Gomez <german.gomez@arm.com>,
        Changbin Du <changbin.du@huawei.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        liuwenyu <liuwenyu7@huawei.com>, linux-kernel@vger.kernel.org,
        linux-perf-users@vger.kernel.org
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Precedence: bulk

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 e541d0e2777a..e9ff78b331fe 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>
@@ -4314,34 +4315,38 @@ 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_ */
-- 
2.42.0.758.gaed0368e0e-goog