[PATCH v8 05/17] perf machine: Use perf_env e_machine rather than arch

Ian Rogers
2026-05-02T07:00:03Z

The arch string is derived from uname and may be normalized causing
potential differences meaning the ELF machine can be more
precise. Reduce the scope of machine__is as often it is better to use
a thread for the e_machine rather than the machine. Switch from string
to ELF machine constant comparisons.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/machine.c | 25 ++++++++-----------------
tools/perf/util/machine.h | 2 --
2 files changed, 8 insertions(+), 19 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index e76f8c86e62a..6d32d3cb5cb7 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1611,10 +1611,15 @@ static bool machine__uses_kcore(struct machine *machine)
return dsos__for_each_dso(&machine->dsos, machine__uses_kcore_cb, NULL) != 0 ? true : false;
}

+static bool machine__is(struct machine *machine, uint16_t e_machine)
+{
+ return machine && perf_env__e_machine(machine->env, NULL) == e_machine;
+}
+
static bool perf_event__is_extra_kernel_mmap(struct machine *machine,
struct extra_kernel_map *xm)
{
- return machine__is(machine, "x86_64") &&
+ return machine__is(machine, EM_X86_64) &&
is_entry_trampoline(xm->name);
}

@@ -2770,7 +2775,7 @@ static int find_prev_cpumode(struct ip_callchain *chain, struct thread *thread,
static u64 get_leaf_frame_caller(struct perf_sample *sample,
struct thread *thread, int usr_idx)
{
- if (machine__normalized_is(maps__machine(thread__maps(thread)), "arm64"))
+ if (thread__e_machine(thread, /*machine=*/NULL, /*e_flags=*/NULL) == EM_AARCH64)
return get_leaf_frame_caller_aarch64(sample, thread, usr_idx);
else
return 0;
@@ -3141,20 +3146,6 @@ int machine__set_current_tid(struct machine *machine, int cpu, pid_t pid,
return 0;
}

-/*
- * Compares the raw arch string. N.B. see instead perf_env__arch() or
- * machine__normalized_is() if a normalized arch is needed.
- */
-bool machine__is(struct machine *machine, const char *arch)
-{
- return machine && !strcmp(perf_env__raw_arch(machine->env), arch);
-}
-
-bool machine__normalized_is(struct machine *machine, const char *arch)
-{
- return machine && !strcmp(perf_env__arch(machine->env), arch);
-}
-
int machine__nr_cpus_avail(struct machine *machine)
{
return machine ? perf_env__nr_cpus_avail(machine->env) : 0;
@@ -3181,7 +3172,7 @@ int machine__get_kernel_start(struct machine *machine)
* start of kernel text, but still above 2^63. So leave
* kernel_start = 1ULL << 63 for x86_64.
*/
- if (!err && !machine__is(machine, "x86_64"))
+ if (!err && !machine__is(machine, EM_X86_64))
machine->kernel_start = map__start(map);
}
return err;
diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
index 22a42c5825fa..003c970b3e4b 100644
--- a/tools/perf/util/machine.h
+++ b/tools/perf/util/machine.h
@@ -227,8 +227,6 @@ static inline bool machine__is_host(struct machine *machine)
}

bool machine__is_lock_function(struct machine *machine, u64 addr);
-bool machine__is(struct machine *machine, const char *arch);
-bool machine__normalized_is(struct machine *machine, const char *arch);
int machine__nr_cpus_avail(struct machine *machine);

struct thread *machine__findnew_thread(struct machine *machine, pid_t pid, pid_t tid);
--
2.54.0.545.g6539524ca2-goog