From cd420e085a93fc65397b9c27d615e8d8905a5b10 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jaroslav=20=C5=A0karvada?= <jskarvad@redhat.com>
Date: Mon, 2 Dec 2024 17:44:15 +0100
Subject: [PATCH] plugin_scheduler: make perf support optional
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Requested in: https://src.fedoraproject.org/rpms/tuned/pull-request/8

Signed-off-by: Jaroslav Škarvada <jskarvad@redhat.com>
---
 tuned.spec                        |  9 +++++----
 tuned/consts.py                   |  3 +++
 tuned/plugins/plugin_scheduler.py | 18 ++++++++++++++++--
 3 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/tuned.spec b/tuned.spec
index a9ccef65..eceec8e5 100644
--- a/tuned.spec
+++ b/tuned.spec
@@ -83,7 +83,7 @@ BuildRequires: %{_py}-mock
 %endif
 BuildRequires: %{_py}-pyudev
 Requires: %{_py}-pyudev
-Requires: %{_py}-linux-procfs, %{_py}-perf
+Requires: %{_py}-linux-procfs
 %if %{without python3}
 Requires: %{_py}-schedutils
 %endif
@@ -92,9 +92,6 @@ Requires: %{_py}-schedutils
 # BuildRequires for 'make test'
 BuildRequires: python3-dbus, python3-gobject-base
 Requires: python3-dbus, python3-gobject-base
-%if 0%{?fedora} > 22 || 0%{?rhel} > 7
-Recommends: dmidecode
-%endif
 %else
 # BuildRequires for 'make test'
 BuildRequires: dbus-python, pygobject3-base
@@ -104,11 +101,15 @@ Requires: virt-what, ethtool, gawk
 Requires: util-linux, dbus, polkit
 %if 0%{?fedora} > 22 || 0%{?rhel} > 7
 Recommends: dmidecode
+# https://src.fedoraproject.org/rpms/tuned/pull-request/8
+Recommends: %{_py}-perf
 # i686 excluded
 Recommends: kernel-tools
 Requires: hdparm
 Requires: kmod
 Requires: iproute
+%else
+Requires: %{_py}-perf
 %endif
 # syspurpose
 %if 0%{?rhel} > 8
diff --git a/tuned/consts.py b/tuned/consts.py
index 4606aee1..9fe79ad0 100644
--- a/tuned/consts.py
+++ b/tuned/consts.py
@@ -77,6 +77,9 @@
 # built-in functions configuration
 SYSFS_CPUS_PATH = "/sys/devices/system/cpu"
 
+# present CPUs
+SYSFS_CPUS_PRESENT_PATH = "%s/present" % SYSFS_CPUS_PATH
+
 # number of backups
 LOG_FILE_COUNT = 2
 LOG_FILE_MAXBYTES = 100*1000
diff --git a/tuned/plugins/plugin_scheduler.py b/tuned/plugins/plugin_scheduler.py
index 7d9bcbe0..a628bdc2 100644
--- a/tuned/plugins/plugin_scheduler.py
+++ b/tuned/plugins/plugin_scheduler.py
@@ -8,7 +8,12 @@
 import re
 from subprocess import *
 import threading
-import perf
+# perf is optional
+try:
+	import perf
+except ModuleNotFoundError:
+# if perf is unavailable, it will be disabled later
+	pass
 import select
 import tuned.consts as consts
 import procfs
@@ -447,7 +452,15 @@ def __init__(self, monitor_repository, storage_factory, hardware_inventory, devi
 		self._ps_whitelist = ".*"
 		self._ps_blacklist = ""
 		self._cgroup_ps_blacklist_re = ""
-		self._cpus = perf.cpu_map()
+		# perf is optional, if unavailable, it will be disabled later
+		try:
+			self._cpus = perf.cpu_map()
+		except (NameError, AttributeError):
+			cpus = self._cmd.read_file(consts.SYSFS_CPUS_PRESENT_PATH)
+			# it's different type than perf.cpu_map(), but without perf we use it as iterable
+			# which should be compatible, fallback to single core CPU if sysfs is unavailable
+			self._cpus = self._cmd.cpulist_unpack(cpus) if cpus else [ 0 ]
+
 		self._scheduler_storage_key = self._storage_key(
 				command_name = "scheduler")
 		self._irq_process = True
@@ -532,6 +545,7 @@ def _instance_init(self, instance):
 					instance._evlist.mmap(pages = perf_mmap_pages)
 			# no perf
 			except:
+				log.warn("python-perf unavailable, disabling perf support, you can try to (re)install python(3)-perf package")
 				instance._runtime_tuning = False
 
 	def _instance_cleanup(self, instance):