Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1#!/usr/bin/env drgn
2#
3# Copyright (C) 2023 Tejun Heo <tj@kernel.org>
4# Copyright (C) 2023 Meta Platforms, Inc. and affiliates.
5
6desc = """
7This is a drgn script to monitor workqueues. For more info on drgn, visit
8https://github.com/osandov/drgn.
9
10 total Total number of work items executed by the workqueue.
11
12 infl The number of currently in-flight work items.
13
14 CPUtime Total CPU time consumed by the workqueue in seconds. This is
15 sampled from scheduler ticks and only provides ballpark
16 measurement. "nohz_full=" CPUs are excluded from measurement.
17
18 CPUitsv The number of times a concurrency-managed work item hogged CPU
19 longer than the threshold (workqueue.cpu_intensive_thresh_us)
20 and got excluded from concurrency management to avoid stalling
21 other work items.
22
23 CMwake The number of concurrency-management wake-ups while executing a
24 work item of the workqueue.
25
26 mayday The number of times the rescuer was requested while waiting for
27 new worker creation.
28
29 rescued The number of work items executed by the rescuer.
30"""
31
32import sys
33import signal
34import os
35import re
36import time
37import json
38
39import drgn
40from drgn.helpers.linux.list import list_for_each_entry,list_empty
41from drgn.helpers.linux.cpumask import for_each_possible_cpu
42
43import argparse
44parser = argparse.ArgumentParser(description=desc,
45 formatter_class=argparse.RawTextHelpFormatter)
46parser.add_argument('workqueue', metavar='REGEX', nargs='*',
47 help='Target workqueue name patterns (all if empty)')
48parser.add_argument('-i', '--interval', metavar='SECS', type=float, default=1,
49 help='Monitoring interval (0 to print once and exit)')
50parser.add_argument('-j', '--json', action='store_true',
51 help='Output in json')
52args = parser.parse_args()
53
54def err(s):
55 print(s, file=sys.stderr, flush=True)
56 sys.exit(1)
57
58workqueues = prog['workqueues']
59
60WQ_UNBOUND = prog['WQ_UNBOUND']
61WQ_MEM_RECLAIM = prog['WQ_MEM_RECLAIM']
62
63PWQ_STAT_STARTED = prog['PWQ_STAT_STARTED'] # work items started execution
64PWQ_STAT_COMPLETED = prog['PWQ_STAT_COMPLETED'] # work items completed execution
65PWQ_STAT_CPU_TIME = prog['PWQ_STAT_CPU_TIME'] # total CPU time consumed
66PWQ_STAT_CPU_INTENSIVE = prog['PWQ_STAT_CPU_INTENSIVE'] # wq_cpu_intensive_thresh_us violations
67PWQ_STAT_CM_WAKEUP = prog['PWQ_STAT_CM_WAKEUP'] # concurrency-management worker wakeups
68PWQ_STAT_MAYDAY = prog['PWQ_STAT_MAYDAY'] # maydays to rescuer
69PWQ_STAT_RESCUED = prog['PWQ_STAT_RESCUED'] # linked work items executed by rescuer
70PWQ_NR_STATS = prog['PWQ_NR_STATS']
71
72class WqStats:
73 def __init__(self, wq):
74 self.name = wq.name.string_().decode()
75 self.unbound = wq.flags & WQ_UNBOUND != 0
76 self.mem_reclaim = wq.flags & WQ_MEM_RECLAIM != 0
77 self.stats = [0] * PWQ_NR_STATS
78 for pwq in list_for_each_entry('struct pool_workqueue', wq.pwqs.address_of_(), 'pwqs_node'):
79 for i in range(PWQ_NR_STATS):
80 self.stats[i] += int(pwq.stats[i])
81
82 def dict(self, now):
83 return { 'timestamp' : now,
84 'name' : self.name,
85 'unbound' : self.unbound,
86 'mem_reclaim' : self.mem_reclaim,
87 'started' : self.stats[PWQ_STAT_STARTED],
88 'completed' : self.stats[PWQ_STAT_COMPLETED],
89 'cpu_time' : self.stats[PWQ_STAT_CPU_TIME],
90 'cpu_intensive' : self.stats[PWQ_STAT_CPU_INTENSIVE],
91 'cm_wakeup' : self.stats[PWQ_STAT_CM_WAKEUP],
92 'mayday' : self.stats[PWQ_STAT_MAYDAY],
93 'rescued' : self.stats[PWQ_STAT_RESCUED], }
94
95 def table_header_str():
96 return f'{"":>24} {"total":>8} {"infl":>5} {"CPUtime":>8} '\
97 f'{"CPUitsv":>7} {"CMwake":>7} {"mayday":>7} {"rescued":>7}'
98
99 def table_row_str(self):
100 cpu_intensive = '-'
101 cm_wakeup = '-'
102 mayday = '-'
103 rescued = '-'
104
105 if not self.unbound:
106 cpu_intensive = str(self.stats[PWQ_STAT_CPU_INTENSIVE])
107 cm_wakeup = str(self.stats[PWQ_STAT_CM_WAKEUP])
108
109 if self.mem_reclaim:
110 mayday = str(self.stats[PWQ_STAT_MAYDAY])
111 rescued = str(self.stats[PWQ_STAT_RESCUED])
112
113 out = f'{self.name[-24:]:24} ' \
114 f'{self.stats[PWQ_STAT_STARTED]:8} ' \
115 f'{max(self.stats[PWQ_STAT_STARTED] - self.stats[PWQ_STAT_COMPLETED], 0):5} ' \
116 f'{self.stats[PWQ_STAT_CPU_TIME] / 1000000:8.1f} ' \
117 f'{cpu_intensive:>7} ' \
118 f'{cm_wakeup:>7} ' \
119 f'{mayday:>7} ' \
120 f'{rescued:>7} '
121 return out.rstrip(':')
122
123exit_req = False
124
125def sigint_handler(signr, frame):
126 global exit_req
127 exit_req = True
128
129def main():
130 # handle args
131 table_fmt = not args.json
132 interval = args.interval
133
134 re_str = None
135 if args.workqueue:
136 for r in args.workqueue:
137 if re_str is None:
138 re_str = r
139 else:
140 re_str += '|' + r
141
142 filter_re = re.compile(re_str) if re_str else None
143
144 # monitoring loop
145 signal.signal(signal.SIGINT, sigint_handler)
146
147 while not exit_req:
148 now = time.time()
149
150 if table_fmt:
151 print()
152 print(WqStats.table_header_str())
153
154 for wq in list_for_each_entry('struct workqueue_struct', workqueues.address_of_(), 'list'):
155 stats = WqStats(wq)
156 if filter_re and not filter_re.search(stats.name):
157 continue
158 if table_fmt:
159 print(stats.table_row_str())
160 else:
161 print(stats.dict(now))
162
163 if interval == 0:
164 break
165 time.sleep(interval)
166
167if __name__ == "__main__":
168 main()