sysfs: classes for /sys/devices/system/cpu/

So that we can get topology information and do CPU hotplug operations.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 96 insertions, 0 deletions

diff --git a/tuna/sysfs.py b/tuna/sysfs.py
new file mode 100644
index 0000000..5763555
--- /dev/null
+++ b/tuna/sysfs.py
@@ -0,0 +1,96 @@
+#! /usr/bin/python
+# -*- python -*-
+# -*- coding: utf-8 -*-
+
+import os
+
+class cpu:
+	def __init__(self, basedir, name):
+		self.name = name
+		self.dir = "%s/%s" % (basedir, name)
+		self.reload()
+
+	def readfile(self, name):
+		try:
+			f = open("%s/%s" % (self.dir, name))
+			value = f.readline().strip()
+			f.close()
+		except:
+			raise
+		return value
+
+	def reload_online(self):
+		self.online = True
+		try:
+			self.online = self.readfile("online") == "1"
+		except:
+			# boot CPU, usually cpu0, can't be brought offline, so
+			# lacks the file and non root users can't read. In both
+			# cases assume CPU is online.
+			pass
+
+	def reload(self):
+		self.reload_online()
+		if self.online:
+			self.physical_package_id = self.readfile("topology/physical_package_id")
+		else:
+			self.physical_package_id = None
+
+	def set_online(self, online = True):
+		try:
+			f = open("%s/online" % self.dir, "w")
+			f.write("%d\n" % (online and 1 or 0))
+			f.close()
+		except:
+			pass
+
+		self.reload_online()
+		return online == self.online
+
+class cpus:
+	def __init__(self, basedir = "/sys/devices/system/cpu"):
+		self.basedir = basedir
+		self.cpus = {}
+		self.sockets = {}
+		self.reload()
+		self.nr_cpus = len(self.cpus)
+
+	def __getitem__(self, key):
+		return self.cpus[key]
+
+	def keys(self):
+		return self.cpus.keys()
+
+	def has_key(self, key):
+		return self.cpus.has_key(key)
+
+	def reload(self):
+		for name in os.listdir(self.basedir):
+			if name[:3] != "cpu":
+				continue
+
+			if name in self.cpus:
+				self.cpus[name].reload(self.basedir)
+			else:
+				c = cpu(self.basedir, name)
+				self.cpus[name] = c
+				socket = c.physical_package_id
+				if socket in self.sockets:
+					self.sockets[socket].insert(0, c)
+				else:
+					self.sockets[socket] = [ c, ]
+
+if __name__ == '__main__':
+	import sys
+
+	cpus = cpus()
+
+	for socket in cpus.sockets.keys():
+		print "Socket %s" % socket
+		for c in cpus.sockets[socket]:
+			print "  %s" % c.name
+			print "    online: %s" % c.online
+			c.set_online(False)
+			print "    online: %s" % c.online
+			c.set_online()
+			print "    online: %s" % c.online