python: tools: Add tool for displaying a list of PSI data

Add a tool for displaying the PSI data for a cgroup hierarchy.

$ ./src/tools/cgpsilist.py -c cpu -d 1 -f some-avg10 -l 10 -t 0
some-avg10 PSI CGROUP
          0.00 /sys-fs-fuse-connections.mount
          0.00 /sys-kernel-config.mount
          0.00 /sys-kernel-debug.mount
          0.00 /dev-mqueue.mount
          0.00 /user.slice
          0.00 /sys-kernel-tracing.mount
          0.00 /init.scope
          0.00 /system.slice
          0.00 /proc-sys-fs-binfmt_misc.mount
          0.00 /machine.slice

$ ./src/tools/cgpsilist.py -c cpu -d 1 -f full-total -l 10 -t 0
full-total PSI CGROUP
     421304531 /user.slice
      62664636 /system.slice
        118774 /init.scope
           109 /sys-kernel-debug.mount
             7 /dev-hugepages.mount
             3 /sys-fs-fuse-connections.mount
             3 /sys-kernel-tracing.mount
             3 /proc-sys-fs-binfmt_misc.mount
             0 /sys-kernel-config.mount
             0 /dev-mqueue.mount

Signed-off-by: Tom Hromatka <[email protected]>

src/python/libcgroup.pyx.m4

@@ -1162,6 +1162,59 @@ class LibcgroupList(LibcgroupTree):
                       cgpid.pidstats['Command'], cgpid.pidstats[self.metric],
                       cgpid.cgroup))
 
+class LibcgroupPsiList(LibcgroupTree):
+    def __init__(self, name, controller='cpu', depth=None, psi_field='some-avg10',
+                 threshold=None, limit=None):
+        super().__init__(name, version=Version.CGROUP_V2, controller=controller,
+                         depth=depth)
+
+        self.controller = controller
+        self.psi_field = psi_field
+        self.cglist = list()
+        self.threshold = threshold
+        self.limit = limit
+
+    def walk_action(self, cg):
+        cg.get_psi(self.controller)
+
+        if not self.threshold:
+            self.cglist.append(cg)
+        elif cg.psi[self.psi_field] >= self.threshold:
+            self.cglist.append(cg)
+
+    def sort(self):
+        self.cglist = sorted(self.cglist, reverse=True,
+                             key=lambda cg: cg.psi[self.psi_field])
+
+    def _show_float(self):
+        print('{0: >10} {1: >3} {2: <16}'.`format'(self.psi_field, 'PSI', 'CGROUP'))
+
+        for i, cg in enumerate(self.cglist):
+            if self.limit and i >= self.limit:
+                break
+
+            print('        {0: 6.2f} {1: <16}'.`format'(cg.psi[self.psi_field],
+                                                        cg.path[`len'(self.start_path):]))
+
+    def _show_int(self):
+        print('{0: >10} {1: >3} {2: <16}'.`format'(self.psi_field, 'PSI', 'CGROUP'))
+
+        for i, cg in enumerate(self.cglist):
+            if self.limit and i >= self.limit:
+                break
+
+            print('   {0: 11d} {1: <16}'.`format'(cg.psi[self.psi_field],
+                                                  cg.path[`len'(self.start_path):]))
+
+    def show(self, sort=True):
+        if sort:
+            self.sort()
+
+        if 'total' in self.psi_field:
+            self._show_int()
+        else:
+            self._show_float()
+
 class LibcgroupPid(object):
     def __init__(self, pid, command=None):
         self.pid = pid

src/tools/Makefile.am

@@ -71,6 +71,7 @@ cgsnapshot_CFLAGS = $(CODE_COVERAGE_CFLAGS) $(EXTRA_CFLAGS)
 
 if ENABLE_PYTHON
 EXTRA_DIST = \
+	cgpsilist.py \
 	cgpsitree.py
 endif
 

src/tools/cgpsilist.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: LGPL-2.1-only
+#
+# Display a list of cgroups and their specified PSI metrics
+#
+# Copyright (c) 2021-2024 Oracle and/or its affiliates.
+# Author: Tom Hromatka <[email protected]>
+#
+
+from libcgroup import LibcgroupPsiList
+import argparse
+import os
+
+def parse_args():
+    parser = argparse.ArgumentParser('Libcgroup PSI List')
+    parser.add_argument('-C', '--cgroup', type=str, required=False, default=None,
+                        help='Relative path to the cgroup of interest, e.g. machine.slice/foo.scope')
+    parser.add_argument('-c', '--controller', required=True,
+                        help='PSI controller data to display.  cpu, io, or memory')
+    parser.add_argument('-f', '--field', required=False, default='some-avg10',
+                        help='Which PSI field to display, e.g. some-avg10, full-avg60, ...')
+    parser.add_argument('-d', '--depth', type=int, required=False, default=None,
+                        help='Depth to recurse into the cgroup path.  0 == only this cgroup, 1 == this cgroup and its children, ...')
+    parser.add_argument('-t', '--threshold', type=float, required=False, default=1.0,
+                        help='Only list cgroups whose PSI exceeds this percentage')
+    parser.add_argument('-l', '--limit', type=int, required=False, default=None,
+                        help='Only display the first N cgroups. If not provided, all cgroups that match are displayed')
+
+    args = parser.parse_args()
+
+    return args
+
+def main(args):
+    cglist = LibcgroupPsiList(args.cgroup, controller=args.controller, depth=args.depth,
+                              psi_field=args.field, threshold=args.threshold, limit=args.limit)
+
+    cglist.walk()
+    cglist.show()
+
+if __name__ == '__main__':
+    args = parse_args()
+    main(args)