tools/power turbostat: Add selftests for SMI, APERF and MPERF counters

The test requests BICs that are dependent on SMI, APERF and MPERF
counters and checks if the columns show up in the output and the
turbostat doesn't crash. Read the counters in both --no-msr
and --no-perf mode.

The test skips counters that are not present or user does not have
permissions to read. It is not an error, but the test may not be as
exhaustive.
Signed-off-by: Patryk Wlazlyn <patryk.wlazlyn@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

tools/testing/selftests/turbostat/smi_aperf_mperf.py

+#!/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+import subprocess
+from shutil import which
+from os import pread
+
+# CDLL calls dlopen underneath.
+# Calling it with None (null), we get handle to the our own image (python interpreter).
+# We hope to find sched_getcpu() inside ;]
+# This is a bit ugly, but helps shipping working software, so..
+try:
+	import ctypes
+
+	this_image = ctypes.CDLL(None)
+	BASE_CPU = this_image.sched_getcpu()
+except:
+	BASE_CPU = 0 # If we fail, set to 0 and pray it's not offline.
+
+MSR_IA32_MPERF = 0x000000e7
+MSR_IA32_APERF = 0x000000e8
+
+def check_perf_access():
+	perf = which('perf')
+	if perf is None:
+		print('SKIP: Could not find perf binary, thus could not determine perf access.')
+		return False
+
+	def has_perf_counter_access(counter_name):
+		proc_perf = subprocess.run([perf, 'stat', '-e', counter_name, '--timeout', '10'],
+					    capture_output = True)
+
+		if proc_perf.returncode != 0:
+			print(f'SKIP: Could not read {counter_name} perf counter, assuming no access.')
+			return False
+
+		if b'<not supported>' in proc_perf.stderr:
+			print(f'SKIP: Could not read {counter_name} perf counter, assuming no access.')
+			return False
+
+		return True
+
+	if not has_perf_counter_access('msr/mperf/'):
+		return False
+	if not has_perf_counter_access('msr/aperf/'):
+		return False
+	if not has_perf_counter_access('msr/smi/'):
+		return False
+
+	return True
+
+def check_msr_access():
+	try:
+		file_msr = open(f'/dev/cpu/{BASE_CPU}/msr', 'rb')
+	except:
+		return False
+
+	if len(pread(file_msr.fileno(), 8, MSR_IA32_MPERF)) != 8:
+		return False
+
+	if len(pread(file_msr.fileno(), 8, MSR_IA32_APERF)) != 8:
+		return False
+
+	return True
+
+has_perf_access = check_perf_access()
+has_msr_access = check_msr_access()
+
+turbostat_counter_source_opts = ['']
+
+if has_msr_access:
+	turbostat_counter_source_opts.append('--no-perf')
+else:
+	print('SKIP: doesn\'t have MSR access, skipping run with --no-perf')
+
+if has_perf_access:
+	turbostat_counter_source_opts.append('--no-msr')
+else:
+	print('SKIP: doesn\'t have perf access, skipping run with --no-msr')
+
+if not has_msr_access and not has_perf_access:
+	print('SKIP: No MSR nor perf access detected. Skipping the tests entirely')
+	exit(0)
+
+turbostat = which('turbostat')
+if turbostat is None:
+	print('Could not find turbostat binary')
+	exit(1)
+
+timeout = which('timeout')
+if timeout is None:
+	print('Could not find timeout binary')
+	exit(1)
+
+proc_turbostat = subprocess.run([turbostat, '--list'], capture_output = True)
+if proc_turbostat.returncode != 0:
+	print(f'turbostat failed with {proc_turbostat.returncode}')
+	exit(1)
+
+EXPECTED_COLUMNS_DEBUG_DEFAULT = b'usec\tTime_Of_Day_Seconds\tAPIC\tX2APIC'
+
+SMI_APERF_MPERF_DEPENDENT_BICS = [
+	'SMI',
+	'Avg_MHz',
+	'Busy%',
+	'Bzy_MHz',
+]
+if has_perf_access:
+	SMI_APERF_MPERF_DEPENDENT_BICS.append('IPC')
+
+for bic in SMI_APERF_MPERF_DEPENDENT_BICS:
+	for counter_source_opt in turbostat_counter_source_opts:
+
+		# Ugly special case, but it is what it is..
+		if counter_source_opt == '--no-perf' and bic == 'IPC':
+			continue
+
+		expected_columns = bic.encode()
+		expected_columns_debug = EXPECTED_COLUMNS_DEBUG_DEFAULT + f'\t{bic}'.encode()
+
+		#
+		# Run turbostat for some time and send SIGINT
+		#
+		timeout_argv = [timeout, '--preserve-status', '-s', 'SIGINT', '-k', '3', '0.2s']
+		turbostat_argv = [turbostat, '-i', '0.50', '--show', bic]
+
+		if counter_source_opt:
+			turbostat_argv.append(counter_source_opt)
+
+		print(f'Running turbostat with {turbostat_argv=}... ', end = '', flush = True)
+		proc_turbostat = subprocess.run(timeout_argv + turbostat_argv, capture_output = True)
+		if proc_turbostat.returncode != 0:
+			print(f'turbostat failed with {proc_turbostat.returncode}')
+			exit(1)
+
+		actual_columns = proc_turbostat.stdout.split(b'\n')[0]
+		if expected_columns != actual_columns:
+			print(f'turbostat column check failed\n{expected_columns=}\n{actual_columns=}')
+			exit(1)
+		print('OK')
+
+		#
+		# Same, but with --debug
+		#
+		turbostat_argv.append('--debug')
+
+		print(f'Running turbostat with {turbostat_argv=}... ', end = '', flush = True)
+		proc_turbostat = subprocess.run(timeout_argv + turbostat_argv, capture_output = True)
+		if proc_turbostat.returncode != 0:
+			print(f'turbostat failed with {proc_turbostat.returncode}')
+			exit(1)
+
+		actual_columns = proc_turbostat.stdout.split(b'\n')[0]
+		if expected_columns_debug != actual_columns:
+			print(f'turbostat column check failed\n{expected_columns_debug=}\n{actual_columns=}')
+			exit(1)
+		print('OK')