linux-kernel - [PATCH v3 5/5] perf thread: Don't require machine to compute the e

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Message-ID: <20260203182640.3911987-6-irogers@google.com>
Date: Tue,  3 Feb 2026 10:26:40 -0800
From: Ian Rogers <irogers@...gle.com>
To: acme@...nel.org
Cc: aditya.b1@...ux.ibm.com, adrian.hunter@...el.com, ajones@...tanamicro.com, 
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Subject: [PATCH v3 5/5] 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@...gle.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) {
-- 
2.53.0.rc2.204.g2597b5adb4-goog