3 # Copyright (C) 2023 Tejun Heo <tj@kernel.org>
4 # Copyright (C) 2023 Meta Platforms, Inc. and affiliates.
7 This is a drgn script to monitor workqueues. For more info on drgn, visit
8 https://github.com/osandov/drgn.
10 total Total number of work items executed by the workqueue.
12 infl The number of currently in-flight work items.
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.
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
23 CMwake The number of concurrency-management wake-ups while executing a
24 work item of the workqueue.
26 mayday The number of times the rescuer was requested while waiting for
29 rescued The number of work items executed by the rescuer.
40 from drgn.helpers.linux.list import list_for_each_entry,list_empty
41 from drgn.helpers.linux.cpumask import for_each_possible_cpu
44 parser = argparse.ArgumentParser(description=desc,
45 formatter_class=argparse.RawTextHelpFormatter)
46 parser.add_argument('workqueue', metavar='REGEX', nargs='*',
47 help='Target workqueue name patterns (all if empty)')
48 parser.add_argument('-i', '--interval', metavar='SECS', type=float, default=1,
49 help='Monitoring interval (0 to print once and exit)')
50 parser.add_argument('-j', '--json', action='store_true',
51 help='Output in json')
52 args = parser.parse_args()
55 print(s, file=sys.stderr, flush=True)
58 workqueues = prog['workqueues']
60 WQ_UNBOUND = prog['WQ_UNBOUND']
61 WQ_MEM_RECLAIM = prog['WQ_MEM_RECLAIM']
63 PWQ_STAT_STARTED = prog['PWQ_STAT_STARTED'] # work items started execution
64 PWQ_STAT_COMPLETED = prog['PWQ_STAT_COMPLETED'] # work items completed execution
65 PWQ_STAT_CPU_TIME = prog['PWQ_STAT_CPU_TIME'] # total CPU time consumed
66 PWQ_STAT_CPU_INTENSIVE = prog['PWQ_STAT_CPU_INTENSIVE'] # wq_cpu_intensive_thresh_us violations
67 PWQ_STAT_CM_WAKEUP = prog['PWQ_STAT_CM_WAKEUP'] # concurrency-management worker wakeups
68 PWQ_STAT_MAYDAY = prog['PWQ_STAT_MAYDAY'] # maydays to rescuer
69 PWQ_STAT_RESCUED = prog['PWQ_STAT_RESCUED'] # linked work items executed by rescuer
70 PWQ_NR_STATS = prog['PWQ_NR_STATS']
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])
83 return { 'timestamp' : now,
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], }
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}'
99 def table_row_str(self):
106 cpu_intensive = str(self.stats[PWQ_STAT_CPU_INTENSIVE])
107 cm_wakeup = str(self.stats[PWQ_STAT_CM_WAKEUP])
110 mayday = str(self.stats[PWQ_STAT_MAYDAY])
111 rescued = str(self.stats[PWQ_STAT_RESCUED])
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} ' \
121 return out.rstrip(':')
125 def sigint_handler(signr, frame):
131 table_fmt = not args.json
132 interval = args.interval
136 for r in args.workqueue:
142 filter_re = re.compile(re_str) if re_str else None
145 signal.signal(signal.SIGINT, sigint_handler)
152 print(WqStats.table_header_str())
154 for wq in list_for_each_entry('struct workqueue_struct', workqueues.address_of_(), 'list'):
156 if filter_re and not filter_re.search(stats.name):
159 print(stats.table_row_str())
161 print(stats.dict(now))
167 if __name__ == "__main__":