From 84cb36da81413c2dff805150b9f4db1524460269 Mon Sep 17 00:00:00 2001
From: Ian Rogers <irogers@google.com>
Date: Tue, 3 Feb 2026 10:26:40 -0800
Subject: [PATCH] perf thread: Don't require machine to compute the e_machine

The machine can be calculated from a thread via its maps.

Don't require the machine argument to simplify callers and also to delay
computing the machine until a little later.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Aditya Bodkhe <aditya.b1@linux.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Jones <ajones@ventanamicro.com>
Cc: Anubhav Shelat <ashelat@redhat.com>
Cc: Anup Patel <anup@brainfault.org>
Cc: Athira Rajeev <atrajeev@linux.ibm.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Chun-Tse Shao <ctshao@google.com>
Cc: Dapeng Mi <dapeng1.mi@linux.intel.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <pjw@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quan Zhou <zhouquan@iscas.ac.cn>
Cc: Shimin Guo <shimin.guo@skydio.com>
Cc: Swapnil Sapkal <swapnil.sapkal@amd.com>
Cc: Thomas Falcon <thomas.falcon@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yunseong Kim <ysk@kzalloc.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/scripting-engines/trace-event-python.c | 8 +++-----
 tools/perf/util/session.c                              | 3 +--
 tools/perf/util/thread.c                               | 5 +++++
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index 62c9c73daef5..2b0df7bd9a46 100644
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -837,7 +837,6 @@ static PyObject *get_perf_sample_dict(struct perf_sample *sample,
 					 PyObject *callchain)
 {
 	PyObject *dict, *dict_sample, *brstack, *brstacksym;
-	struct machine *machine;
 	uint16_t e_machine = EM_HOST;
 	uint32_t e_flags = EF_HOST;
 
@@ -926,10 +925,9 @@ static PyObject *get_perf_sample_dict(struct perf_sample *sample,
 			PyLong_FromUnsignedLongLong(sample->cyc_cnt));
 	}
 
-	if (al->thread) {
-		machine = maps__machine(thread__maps(al->thread));
-		e_machine = thread__e_machine(al->thread, machine, &e_flags);
-	}
+	if (al->thread)
+		e_machine = thread__e_machine(al->thread, /*machine=*/NULL, &e_flags);
+
 	if (set_regs_in_dict(dict, sample, evsel, e_machine, e_flags))
 		Py_FatalError("Failed to setting regs in dict");
 
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 53f51c3f9603..4b465abfa36c 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -2972,9 +2972,8 @@ struct perf_session__e_machine_cb_args {
 static int perf_session__e_machine_cb(struct thread *thread, void *_args)
 {
 	struct perf_session__e_machine_cb_args *args = _args;
-	struct machine *machine = maps__machine(thread__maps(thread));
 
-	args->e_machine = thread__e_machine(thread, machine, &args->e_flags);
+	args->e_machine = thread__e_machine(thread, /*machine=*/NULL, &args->e_flags);
 	return args->e_machine != EM_NONE ? 1 : 0;
 }
 
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 618f29afb160..22be77225bb0 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -499,6 +499,11 @@ uint16_t thread__e_machine(struct thread *thread, struct machine *machine, uint3
 		return e_machine;
 	}
 
+	if (machine == NULL) {
+		struct maps *maps = thread__maps(thread);
+
+		machine = maps__machine(maps);
+	}
 	tid = thread__tid(thread);
 	pid = thread__pid(thread);
 	if (pid != tid) {