tuna: Implement saving current kthread sched policy and rtprio as an rtctl file

It obeys --threads and --cpus filters, so its possible to:

[root@doppio tuna]# ps ax | grep sirq-net-
    7 ?        S<     0:00 [sirq-net-tx/0]
    8 ?        S<     0:17 [sirq-net-rx/0]
   20 ?        S<     0:00 [sirq-net-tx/1]
   21 ?        S<     0:21 [sirq-net-rx/1]
 3372 pts/1    R+     0:00 grep sirq-net-
[root@doppio tuna]# ./tuna-cmd.py --threads=7,8,20,21 --save /tmp/sirq
[root@doppio tuna]# cat /tmp/sirq
 Generated by tuna
 #
 # Use it with rtctl:
 #
 # rtctl --file /tmp/sirq reset
 #
 # Please use 'man rtctl' for more operations
 #
 # Associate processes into named groups with default priority and
 # scheduling policy.
 #
 # Format is: <groupname>:<sched>:<prio>:<regex>
 #
 # groupname must start at beginning of line.
 # sched must be one of: 'f' (fifo)
 #                       'b' (batch)
 #                       'r' (round-robin)
 #                       'o' (other)
 #                       '*' (leave alone)
 # regex is an awk regex
 #
 # The regex is matched against process names as printed by "ps -eo cmd".

 kthreads:*:1:\[.*\]$

 sirq-net-rx:f:80:\[(sirq|softirq)-net-rx\/.*\]$
 sirq-net-tx:f:80:\[(sirq|softirq)-net-tx\/.*\]$
 [root@doppio tuna]#

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

2 files changed, 99 insertions, 2 deletions

diff --git a/tuna-cmd.py b/tuna-cmd.py
index 64a328d..7d5b296 100755
--- a/tuna-cmd.py
+++ b/tuna-cmd.py
@@ -16,6 +16,12 @@
 import getopt, procfs, sys
 from tuna import tuna
 
+try:
+	from sets import Set as set
+except:
+	# OK, we're modern, having sets as first class citizens
+	pass
+
 # FIXME: ETOOMANYGLOBALS, we need a class!
 
 nr_cpus = None
@@ -33,6 +39,7 @@ def usage():
 	-K, --no_kthreads		Operations will not affect kernel threads
 	-m, --move			move selected entities to CPU-LIST
 	-p, --priority=[POLICY]:RTPRIO	set thread scheduler POLICY and RTPRIO
+	-s, --save=FILENAME		save kthreads sched tunables to FILENAME
 	-t, --threads=THREAD-LIST	THREAD-LIST affected by commands
 	-U, --no_uthreads		Operations will not affect user threads
 	-W, --what_is			Provides help about selected entities'''
@@ -58,15 +65,25 @@ def thread_help(tid):
 	help, title = tuna.kthread_help_plain_text(tid, cmdline)
 	print "%s\n\n%s" % (title, help)
 
+def save(cpus, threads, filename):
+	kthreads = tuna.get_kthread_sched_tunings()
+	for name in kthreads.keys():
+		kt = kthreads[name]
+		if (cpus and not set(kt.affinity).intersection(set(cpus))) or \
+		   (threads and kt.pid not in threads) :
+			del kthreads[name]
+	tuna.generate_rtgroups(filename, kthreads)
+
 def main():
 	try:
 		opts, args = getopt.getopt(sys.argv[1:],
-					   "c:CfghiIKmp:t:UW",
+					   "c:CfghiIKmp:s:t:UW",
 					   ("cpus=", "affect_children",
 					    "filter", "gui", "help",
 					    "isolate", "include",
 					    "no_kthreads",
-					    "move", "priority", "threads=",
+					    "move", "priority",
+					    "save=", "threads=",
 					    "no_uthreads", "what_is"))
 	except getopt.GetoptError, err:
 		usage()
@@ -116,6 +133,8 @@ def main():
 				print "tuna: --move requires a thread list!"
 				sys.exit(2)
 			tuna.move_threads_to_cpu(cpus, threads)
+		elif o in ("-s", "--save"):
+			save(cpus, threads, a)
 		elif o in ("-K", "--no_kthreads"):
 			kthreads = False
 		elif o in ("-U", "--no_uthreads"):
diff --git a/tuna/tuna.py b/tuna/tuna.py
index 12a8048..f7d4885 100755
--- a/tuna/tuna.py
+++ b/tuna/tuna.py
@@ -334,3 +334,81 @@ def threads_set_priority(tids, parm, affect_children = False):
 			for child in [int (a) for a in os.listdir("/proc/%d/task" % tid)]:
 				if child != tid:
 					thread_set_priority(child, policy, rtprio)
+
+class sched_tunings:
+	def __init__(self, name, pid, policy, rtprio, affinity):
+		self.name = name
+		self.pid = pid
+		self.policy = policy
+		self.rtprio = int(rtprio)
+		self.affinity = affinity
+
+def get_kthread_sched_tunings(proc = None):
+	if not proc:
+		proc = procfs.pidstats()
+
+	kthreads = {}
+	for pid in proc.keys():
+		if iskthread(pid):
+			name = proc[pid]["stat"]["comm"]
+			rtprio = int(proc[pid]["stat"]["rt_priority"])
+			policy = schedutils.get_scheduler(pid)
+			affinity = schedutils.get_affinity(pid)
+			kthreads[name] = sched_tunings(name, pid, policy,
+						       rtprio, affinity)
+
+	return kthreads
+
+def generate_rtgroups(filename, kthreads):
+	f = file(filename, "w")
+	f.write('''# Generated by tuna
+#
+# Use it with rtctl:
+# 
+# rtctl --file %s reset
+#
+# Please use 'man rtctl' for more operations
+#
+# Associate processes into named groups with default priority and 
+# scheduling policy.
+#
+# Format is: <groupname>:<sched>:<prio>:<regex>
+#
+# groupname must start at beginning of line.
+# sched must be one of: 'f' (fifo)
+#                       'b' (batch)
+#                       'r' (round-robin)
+#                       'o' (other) 
+#                       '*' (leave alone)
+# regex is an awk regex
+#
+# The regex is matched against process names as printed by "ps -eo cmd".
+
+''' % filename)
+	f.write("kthreads:*:1:\[.*\]$\n\n")
+
+	per_cpu_kthreads = []
+	names = kthreads.keys()
+	names.sort()
+	for name in names:
+		kt = kthreads[name]
+		try:
+			idx = name.index("/")
+			common = name[:idx]
+			if common in per_cpu_kthreads:
+				continue
+			per_cpu_kthreads.append(common)
+			name = common
+			if common[:5] == "sirq-":
+				common = "(sirq|softirq)" + common[4:]
+			elif common[:8] == "softirq-":
+				common = "(sirq|softirq)" + common[7:]
+				name = "s" + name[4:]
+			regex = common + "\/.*" 
+		except:
+			regex = name
+			pass
+		f.write("%s:%c:%d:\[%s\]$\n" % (name,
+						schedutils.schedstr(kt.policy)[6].lower(),
+						kt.rtprio, regex))
+	f.close()