CSIT-470 Add option to configure CFS scheduler priority for VPP

[csit.git] / resources / libraries / python / SchedUtils.py

diff --git a/resources/libraries/python/SchedUtils.py b/resources/libraries/python/SchedUtils.py
new file mode 100644 (file)
index 0000000..ec18b98
--- /dev/null
+++ b/resources/libraries/python/SchedUtils.py
@@ -0,0 +1,104 @@
+# Copyright (c) 2016 Cisco and/or its affiliates.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Linux scheduler util library"""
+from resources.libraries.python.ssh import SSH
+
+
+__all__ = ["SchedUtils"]
+
+class SchedUtils(object):
+    """General class for any linux scheduler related methods/functions."""
+
+    @staticmethod
+    def set_vpp_scheduling_rr(node):
+        """Set real-time scheduling attributes of VPP worker threads to
+        SCHED_RR with priority 1.
+
+        :param node: DUT node with running VPP.
+        :type node: dict
+        :raises RuntimeError: Failed to retrieve PID for VPP worker threads.
+        """
+        ssh = SSH()
+        ssh.connect(node)
+
+        cmd = "cat /proc/`pidof vpp`/task/*/stat | grep -i vpp_wk"\
+            " | awk '{print $1}'"
+
+        for _ in range(3):
+            (ret, out, _) = ssh.exec_command_sudo(cmd)
+            if ret == 0:
+                try:
+                    if not out:
+                        raise ValueError
+                except ValueError:
+                    print 'Reading VPP worker thread PID failed.'
+                else:
+                    for pid in out.split("\n"):
+                        if len(pid) > 0 and pid[0] != "#":
+                            SchedUtils.set_proc_scheduling_rr(node, int(pid))
+                    break
+        else:
+            raise RuntimeError('Failed to retrieve PID for VPP worker threads.')
+
+    @staticmethod
+    def set_proc_scheduling_rr(node, pid, priority=1):
+        """Set real-time scheduling of a process to SCHED_RR with priority for
+        specified PID.
+
+        :param node: Node where to apply scheduling changes.
+        :param pid: Process ID.
+        :param priority: Realtime priority in range 1-99. Default is 1.
+        :type node: dict
+        :type pid: int
+        :type priority: int
+        :raises ValueError: Parameters out of allowed ranges.
+        :raises RuntimeError: Failed to set policy for PID.
+        """
+        ssh = SSH()
+        ssh.connect(node)
+
+        if pid < 1:
+            raise ValueError("SCHED_RR: PID must be higher then 1.")
+
+        if 1 <= priority <= 99:
+            cmd = "chrt -r -p {0} {1}".format(priority, pid)
+            (ret, _, _) = ssh.exec_command_sudo(cmd)
+            if ret != 0:
+                raise RuntimeError("SCHED_RR: Failed to set policy "\
+                    "for PID {0}.".format(pid))
+        else:
+            raise ValueError("SCHED_RR: Priority must be in range 1-99.")
+
+    @staticmethod
+    def set_proc_scheduling_other(node, pid):
+        """Set normal scheduling of a process to SCHED_OTHER for specified PID.
+
+        :param node: Node where to apply scheduling changes.
+        :param pid: Process ID.
+        :type node: dict
+        :type pid: int
+        :raises ValueError: Parameters out of allowed ranges.
+        :raises RuntimeError: Failed to set policy for PID.
+        """
+        ssh = SSH()
+        ssh.connect(node)
+
+        if pid < 1:
+            raise ValueError("SCHED_OTHER: PID must be higher then 1.")
+
+        cmd = "chrt -o -p 0 {1}".format(pid)
+        (ret, _, _) = ssh.exec_command_sudo(cmd)
+        if ret != 0:
+            raise RuntimeError("SCHED_OTHER: Failed to set policy "\
+                    "for PID {0}.".format(pid))