forked from iovisor/bcc
-
Notifications
You must be signed in to change notification settings - Fork 0
/
offwaketime.py
executable file
·393 lines (355 loc) · 14 KB
/
offwaketime.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
#!/usr/bin/python
#
# offwaketime Summarize blocked time by kernel off-CPU stack + waker stack
# For Linux, uses BCC, eBPF.
#
# USAGE: offwaketime [-h] [-p PID | -u | -k] [-U | -K] [-f] [duration]
#
# Copyright 2016 Netflix, Inc.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 20-Jan-2016 Brendan Gregg Created this.
from __future__ import print_function
from bcc import BPF
from time import sleep
import argparse
import signal
import errno
from sys import stderr
# arg validation
def positive_int(val):
try:
ival = int(val)
except ValueError:
raise argparse.ArgumentTypeError("must be an integer")
if ival < 0:
raise argparse.ArgumentTypeError("must be positive")
return ival
def positive_nonzero_int(val):
ival = positive_int(val)
if ival == 0:
raise argparse.ArgumentTypeError("must be nonzero")
return ival
def stack_id_err(stack_id):
# -EFAULT in get_stackid normally means the stack-trace is not availible,
# Such as getting kernel stack trace in userspace code
return (stack_id < 0) and (stack_id != -errno.EFAULT)
# arguments
examples = """examples:
./offwaketime # trace off-CPU + waker stack time until Ctrl-C
./offwaketime 5 # trace for 5 seconds only
./offwaketime -f 5 # 5 seconds, and output in folded format
./offwaketime -m 1000 # trace only events that last more than 1000 usec
./offwaketime -M 9000 # trace only events that last less than 9000 usec
./offwaketime -p 185 # only trace threads for PID 185
./offwaketime -t 188 # only trace thread 188
./offwaketime -u # only trace user threads (no kernel)
./offwaketime -k # only trace kernel threads (no user)
./offwaketime -U # only show user space stacks (no kernel)
./offwaketime -K # only show kernel space stacks (no user)
"""
parser = argparse.ArgumentParser(
description="Summarize blocked time by kernel stack trace + waker stack",
formatter_class=argparse.RawDescriptionHelpFormatter,
epilog=examples)
thread_group = parser.add_mutually_exclusive_group()
# Note: this script provides --pid and --tid flags but their arguments are
# referred to internally using kernel nomenclature: TGID and PID.
thread_group.add_argument("-p", "--pid", metavar="PID", dest="tgid",
help="trace this PID only", type=positive_int)
thread_group.add_argument("-t", "--tid", metavar="TID", dest="pid",
help="trace this TID only", type=positive_int)
thread_group.add_argument("-u", "--user-threads-only", action="store_true",
help="user threads only (no kernel threads)")
thread_group.add_argument("-k", "--kernel-threads-only", action="store_true",
help="kernel threads only (no user threads)")
stack_group = parser.add_mutually_exclusive_group()
stack_group.add_argument("-U", "--user-stacks-only", action="store_true",
help="show stacks from user space only (no kernel space stacks)")
stack_group.add_argument("-K", "--kernel-stacks-only", action="store_true",
help="show stacks from kernel space only (no user space stacks)")
parser.add_argument("-d", "--delimited", action="store_true",
help="insert delimiter between kernel/user stacks")
parser.add_argument("-f", "--folded", action="store_true",
help="output folded format")
parser.add_argument("--stack-storage-size", default=1024,
type=positive_nonzero_int,
help="the number of unique stack traces that can be stored and "
"displayed (default 1024)")
parser.add_argument("duration", nargs="?", default=99999999,
type=positive_nonzero_int,
help="duration of trace, in seconds")
parser.add_argument("-m", "--min-block-time", default=1,
type=positive_nonzero_int,
help="the amount of time in microseconds over which we " +
"store traces (default 1)")
parser.add_argument("-M", "--max-block-time", default=(1 << 64) - 1,
type=positive_nonzero_int,
help="the amount of time in microseconds under which we " +
"store traces (default U64_MAX)")
parser.add_argument("--ebpf", action="store_true",
help=argparse.SUPPRESS)
args = parser.parse_args()
folded = args.folded
duration = int(args.duration)
# signal handler
def signal_ignore(signal, frame):
print()
# define BPF program
bpf_text = """
#include <uapi/linux/ptrace.h>
#include <linux/sched.h>
#define MINBLOCK_US MINBLOCK_US_VALUEULL
#define MAXBLOCK_US MAXBLOCK_US_VALUEULL
struct key_t {
char waker[TASK_COMM_LEN];
char target[TASK_COMM_LEN];
int w_k_stack_id;
int w_u_stack_id;
int t_k_stack_id;
int t_u_stack_id;
u32 t_pid;
u32 t_tgid;
u32 w_pid;
u32 w_tgid;
};
BPF_HASH(counts, struct key_t);
// Key of this hash is PID of waiting Process,
// value is timestamp when it went into waiting
BPF_HASH(start, u32);
struct wokeby_t {
char name[TASK_COMM_LEN];
int k_stack_id;
int u_stack_id;
int w_pid;
int w_tgid;
};
// Key of the hash is PID of the Process to be waken, value is information
// of the Process who wakes it
BPF_HASH(wokeby, u32, struct wokeby_t);
BPF_STACK_TRACE(stack_traces, STACK_STORAGE_SIZE);
int waker(struct pt_regs *ctx, struct task_struct *p) {
// PID and TGID of the target Process to be waken
u32 pid = p->pid;
u32 tgid = p->tgid;
if (!(THREAD_FILTER)) {
return 0;
}
// Construct information about current (the waker) Process
struct wokeby_t woke = {};
bpf_get_current_comm(&woke.name, sizeof(woke.name));
woke.k_stack_id = KERNEL_STACK_GET;
woke.u_stack_id = USER_STACK_GET;
woke.w_pid = bpf_get_current_pid_tgid();
woke.w_tgid = bpf_get_current_pid_tgid() >> 32;
wokeby.update(&pid, &woke);
return 0;
}
int oncpu(struct pt_regs *ctx, struct task_struct *p) {
// PID and TGID of the previous Process (Process going into waiting)
u32 pid = p->pid;
u32 tgid = p->tgid;
u64 *tsp;
u64 ts = bpf_ktime_get_ns();
// Record timestamp for the previous Process (Process going into waiting)
if (THREAD_FILTER) {
start.update(&pid, &ts);
}
// Calculate current Process's wait time by finding the timestamp of when
// it went into waiting.
// pid and tgid are now the PID and TGID of the current (waking) Process.
pid = bpf_get_current_pid_tgid();
tgid = bpf_get_current_pid_tgid() >> 32;
tsp = start.lookup(&pid);
if (tsp == 0) {
// Missed or filtered when the Process went into waiting
return 0;
}
u64 delta = ts - *tsp;
start.delete(&pid);
delta = delta / 1000;
if ((delta < MINBLOCK_US) || (delta > MAXBLOCK_US)) {
return 0;
}
// create map key
struct key_t key = {};
struct wokeby_t *woke;
bpf_get_current_comm(&key.target, sizeof(key.target));
key.t_pid = pid;
key.t_tgid = tgid;
key.t_k_stack_id = KERNEL_STACK_GET;
key.t_u_stack_id = USER_STACK_GET;
woke = wokeby.lookup(&pid);
if (woke) {
key.w_k_stack_id = woke->k_stack_id;
key.w_u_stack_id = woke->u_stack_id;
key.w_pid = woke->w_pid;
key.w_tgid = woke->w_tgid;
__builtin_memcpy(&key.waker, woke->name, TASK_COMM_LEN);
wokeby.delete(&pid);
}
counts.increment(key, delta);
return 0;
}
"""
# set thread filter
thread_context = ""
if args.tgid is not None:
thread_context = "PID %d" % args.tgid
thread_filter = 'tgid == %d' % args.tgid
elif args.pid is not None:
thread_context = "TID %d" % args.pid
thread_filter = 'pid == %d' % args.pid
elif args.user_threads_only:
thread_context = "user threads"
thread_filter = '!(p->flags & PF_KTHREAD)'
elif args.kernel_threads_only:
thread_context = "kernel threads"
thread_filter = 'p->flags & PF_KTHREAD'
else:
thread_context = "all threads"
thread_filter = '1'
bpf_text = bpf_text.replace('THREAD_FILTER', thread_filter)
# set stack storage size
bpf_text = bpf_text.replace('STACK_STORAGE_SIZE', str(args.stack_storage_size))
bpf_text = bpf_text.replace('MINBLOCK_US_VALUE', str(args.min_block_time))
bpf_text = bpf_text.replace('MAXBLOCK_US_VALUE', str(args.max_block_time))
# handle stack args
kernel_stack_get = "stack_traces.get_stackid(ctx, 0)"
user_stack_get = "stack_traces.get_stackid(ctx, BPF_F_USER_STACK)"
stack_context = ""
if args.user_stacks_only:
stack_context = "user"
kernel_stack_get = "-1"
elif args.kernel_stacks_only:
stack_context = "kernel"
user_stack_get = "-1"
else:
stack_context = "user + kernel"
bpf_text = bpf_text.replace('USER_STACK_GET', user_stack_get)
bpf_text = bpf_text.replace('KERNEL_STACK_GET', kernel_stack_get)
if args.ebpf:
print(bpf_text)
exit()
# initialize BPF
b = BPF(text=bpf_text)
b.attach_kprobe(event="finish_task_switch", fn_name="oncpu")
b.attach_kprobe(event="try_to_wake_up", fn_name="waker")
matched = b.num_open_kprobes()
if matched == 0:
print("0 functions traced. Exiting.")
exit()
# header
if not folded:
print("Tracing blocked time (us) by %s off-CPU and waker stack" %
stack_context, end="")
if duration < 99999999:
print(" for %d secs." % duration)
else:
print("... Hit Ctrl-C to end.")
try:
sleep(duration)
except KeyboardInterrupt:
# as cleanup can take many seconds, trap Ctrl-C:
# print a newline for folded output on Ctrl-C
signal.signal(signal.SIGINT, signal_ignore)
if not folded:
print()
missing_stacks = 0
has_enomem = False
counts = b.get_table("counts")
stack_traces = b.get_table("stack_traces")
need_delimiter = args.delimited and not (args.kernel_stacks_only or
args.user_stacks_only)
for k, v in sorted(counts.items(), key=lambda counts: counts[1].value):
# handle get_stackid errors
if not args.user_stacks_only:
missing_stacks += int(stack_id_err(k.w_k_stack_id))
missing_stacks += int(stack_id_err(k.t_k_stack_id))
has_enomem = has_enomem or (k.w_k_stack_id == -errno.ENOMEM) or \
(k.t_k_stack_id == -errno.ENOMEM)
if not args.kernel_stacks_only:
missing_stacks += int(stack_id_err(k.w_u_stack_id))
missing_stacks += int(stack_id_err(k.t_u_stack_id))
has_enomem = has_enomem or (k.w_u_stack_id == -errno.ENOMEM) or \
(k.t_u_stack_id == -errno.ENOMEM)
waker_user_stack = [] if k.w_u_stack_id < 1 else \
reversed(list(stack_traces.walk(k.w_u_stack_id))[1:])
waker_kernel_stack = [] if k.w_k_stack_id < 1 else \
reversed(list(stack_traces.walk(k.w_k_stack_id))[1:])
target_user_stack = [] if k.t_u_stack_id < 1 else \
stack_traces.walk(k.t_u_stack_id)
target_kernel_stack = [] if k.t_k_stack_id < 1 else \
stack_traces.walk(k.t_k_stack_id)
if folded:
# print folded stack output
line = [k.target.decode('utf-8', 'replace')]
if not args.kernel_stacks_only:
if stack_id_err(k.t_u_stack_id):
line.append("[Missed User Stack]")
else:
line.extend([b.sym(addr, k.t_tgid).decode('utf-8', 'replace')
for addr in reversed(list(target_user_stack)[1:])])
if not args.user_stacks_only:
line.extend(["-"] if (need_delimiter and k.t_k_stack_id > 0 and k.t_u_stack_id > 0) else [])
if stack_id_err(k.t_k_stack_id):
line.append("[Missed Kernel Stack]")
else:
line.extend([b.ksym(addr).decode('utf-8', 'replace')
for addr in reversed(list(target_kernel_stack)[1:])])
line.append("--")
if not args.user_stacks_only:
if stack_id_err(k.w_k_stack_id):
line.append("[Missed Kernel Stack]")
else:
line.extend([b.ksym(addr).decode('utf-8', 'replace')
for addr in reversed(list(waker_kernel_stack))])
if not args.kernel_stacks_only:
line.extend(["-"] if (need_delimiter and k.w_u_stack_id > 0 and k.w_k_stack_id > 0) else [])
if stack_id_err(k.w_u_stack_id):
line.append("[Missed User Stack]")
else:
line.extend([b.sym(addr, k.w_tgid).decode('utf-8', 'replace')
for addr in reversed(list(waker_user_stack))])
line.append(k.waker.decode('utf-8', 'replace'))
print("%s %d" % (";".join(line), v.value))
else:
# print wakeup name then stack in reverse order
print(" %-16s %s %s" % ("waker:", k.waker.decode('utf-8', 'replace'), k.t_pid))
if not args.kernel_stacks_only:
if stack_id_err(k.w_u_stack_id):
print(" [Missed User Stack]")
else:
for addr in waker_user_stack:
print(" %s" % b.sym(addr, k.w_tgid))
if not args.user_stacks_only:
if need_delimiter and k.w_u_stack_id > 0 and k.w_k_stack_id > 0:
print(" -")
if stack_id_err(k.w_k_stack_id):
print(" [Missed Kernel Stack]")
else:
for addr in waker_kernel_stack:
print(" %s" % b.ksym(addr))
# print waker/wakee delimiter
print(" %-16s %s" % ("--", "--"))
if not args.user_stacks_only:
if stack_id_err(k.t_k_stack_id):
print(" [Missed Kernel Stack]")
else:
for addr in target_kernel_stack:
print(" %s" % b.ksym(addr))
if not args.kernel_stacks_only:
if need_delimiter and k.t_u_stack_id > 0 and k.t_k_stack_id > 0:
print(" -")
if stack_id_err(k.t_u_stack_id):
print(" [Missed User Stack]")
else:
for addr in target_user_stack:
print(" %s" % b.sym(addr, k.t_tgid))
print(" %-16s %s %s" % ("target:", k.target.decode('utf-8', 'replace'), k.w_pid))
print(" %d\n" % v.value)
if missing_stacks > 0:
enomem_str = " Consider increasing --stack-storage-size."
print("WARNING: %d stack traces lost and could not be displayed.%s" %
(missing_stacks, (enomem_str if has_enomem else "")),
file=stderr)