forked from soarpenguin/systemtap-script
-
Notifications
You must be signed in to change notification settings - Fork 0
/
tcp-accept-queue
executable file
·284 lines (225 loc) · 6.85 KB
/
tcp-accept-queue
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
#!/usr/bin/env perl
# Copyright (C) Yichun Zhang (agentzh)
# Based on the systemtap script first shown by chaoslawful.
use 5.006001;
use strict;
use warnings;
use Getopt::Long qw( GetOptions );
GetOptions("a=s", \(my $stap_args),
"d", \(my $dump_src),
"distr", \(my $show_distr),
"h", \(my $help),
"limit=i", \(my $limit),
"port=i", \(my $port),
"time=i", \(my $time),
"latency", \(my $check_latency))
or die usage();
if ($help) {
print usage();
exit;
}
if (!defined $port) {
die "No listening port specified by the -p option.\n";
}
if (!defined $limit) {
$limit = 10;
}
if (!defined $stap_args) {
$stap_args = '';
}
if ($stap_args !~ /\b-D\s*MAXACTION=/) {
$stap_args .= " -DMAXACTION=100000";
}
my $ver = `stap --version 2>&1`;
if (!defined $ver) {
die "Systemtap not installed or its \"stap\" utility is not visible to the PATH environment: $!\n";
}
if ($ver =~ /version\s+(\d+\.\d+)/i) {
my $v = $1;
if ($v < 2.1) {
die "ERROR: at least systemtap 2.1 is required but found $v\n";
}
} else {
die "ERROR: unknown version of systemtap:\n$ver\n";
}
my $stap_src;
if ($show_distr) {
# show queue length distribution
my $summary_code = <<_EOC_;
if (max_syn_qlen == 0) {
println("\\nNo new connections found yet.")
} else {
println("\\n=== SYN Queue ===")
printf("min/avg/max: %d/%d/%d\\n",
\@min(syn_qlen_stats), \@avg(syn_qlen_stats), \@max(syn_qlen_stats))
println(\@hist_log(syn_qlen_stats))
println("=== Accept Queue ===")
printf("min/avg/max: %d/%d/%d\\n",
\@min(acc_qlen_stats), \@avg(acc_qlen_stats), \@max(acc_qlen_stats))
println(\@hist_log(acc_qlen_stats))
}
_EOC_
my $postamble = <<_EOC_;
probe end {
$summary_code
}
_EOC_
my $tip;
if (!defined $time) {
$tip = "Hit Ctrl-C to end."
} else {
$tip = "Sampling for $time seconds.";
$postamble .= <<_EOC_;
probe timer.s($time) {
exit()
}
_EOC_
}
$stap_src = <<_EOC_;
global syn_qlen_stats
global acc_qlen_stats
global max_syn_qlen
global max_acc_qlen
probe begin {
warn("Tracing SYN & ACK backlog queue length distribution on the listening port $port...\\n$tip\\n")
}
probe kernel.function("tcp_v4_conn_request") {
tcphdr = __get_skb_tcphdr(\$skb)
dport = __tcp_skb_dport(tcphdr)
if (dport == $port) {
syn_qlen = \@cast(\$sk, "struct inet_connection_sock")->icsk_accept_queue->listen_opt->qlen
syn_qlen_stats <<< syn_qlen
if (max_syn_qlen == 0) {
max_qlen_log = \@cast(\$sk, "struct inet_connection_sock")->icsk_accept_queue->listen_opt->max_qlen_log
max_syn_qlen = (1 << max_qlen_log)
printf("SYN queue length limit: %d\\n", max_syn_qlen)
}
acc_qlen_stats <<< \$sk->sk_ack_backlog
if (max_acc_qlen == 0) {
max_acc_qlen = \$sk->sk_max_ack_backlog
printf("Accept queue length limit: %d\\n", max_acc_qlen)
}
}
}
$postamble
_EOC_
} elsif ($check_latency) {
my $summary_code = <<_EOC_;
if (!found) {
println("\\nNo new connections found yet.")
} else {
println("\\n=== Accept Queueing Latency Distribution (microsends) ===")
printf("min/avg/max: %d/%d/%d\\n",
\@min(latency_stats), \@avg(latency_stats), \@max(latency_stats))
println(\@hist_log(latency_stats))
}
_EOC_
my $postamble = <<_EOC_;
probe end {
$summary_code
}
_EOC_
my $tip;
if (!defined $time) {
$tip = "Hit Ctrl-C to end."
} else {
$tip = "Sampling for $time seconds.";
$postamble .= <<_EOC_;
probe timer.s($time) {
exit()
}
_EOC_
}
$stap_src = <<_EOC_;
global begin_times
global latency_stats
global found
probe begin {
warn("Tracing accept queueing latency on the listening port $port...\\n$tip\\n")
}
probe kernel.function("tcp_openreq_init") {
tcphdr = __get_skb_tcphdr(\$skb)
dport = __tcp_skb_dport(tcphdr)
if (dport == $port) {
begin_times[\$req] = gettimeofday_us()
//printf("tcp openreq init: %p %d\\n", \$req, dport)
}
}
probe kernel.function("inet_csk_accept") {
req = \@cast(\$sk, "struct inet_connection_sock")->icsk_accept_queue->rskq_accept_head
begin = begin_times[req]
if (begin) {
elapsed = gettimeofday_us() - begin
/*
printf("inet csk accept: sk=%p, req=%p, latency=%d\\n", \$sk, req,
elapsed)
*/
latency_stats <<< elapsed
delete begin_times[req]
found = 1
}
}
$postamble
_EOC_
} else {
# trace queue overflows
$stap_src = <<_EOC_;
global count
probe begin {
warn("Tracing SYN & ACK backlog queue overflows on the listening port $port...\\n")
}
probe kernel.function("tcp_v4_conn_request") {
tcphdr = __get_skb_tcphdr(\$skb)
dport = __tcp_skb_dport(tcphdr)
if (dport == $port) {
syn_qlen = \@cast(\$sk, "struct inet_connection_sock")->icsk_accept_queue->listen_opt->qlen
max_syn_qlen_log = \@cast(\$sk, "struct inet_connection_sock")->icsk_accept_queue->listen_opt->max_qlen_log
max_syn_qlen = (2 << max_syn_qlen_log)
if (syn_qlen > max_syn_qlen) {
now = tz_ctime(gettimeofday_s())
printf("[%s] SYN queue is overflown: %d > %d\\n", now, syn_qlen, max_syn_qlen)
count++
}
//printf("syn queue: %d <= %d\\n", qlen, max_qlen)
ack_backlog = \$sk->sk_ack_backlog
max_ack_backlog = \$sk->sk_max_ack_backlog
if (ack_backlog > max_ack_backlog) {
now = tz_ctime(gettimeofday_s())
printf("[%s] ACK backlog queue is overflown: %d > %d\\n", now, ack_backlog, max_ack_backlog)
count++
}
//printf("ACK backlog queue: %d <= %d\\n", ack_backlog, max_ack_backlog)
if (count >= $limit) {
exit()
}
}
}
_EOC_
}
if ($dump_src) {
print $stap_src;
exit;
}
open my $in, "|stap --all-modules $stap_args -"
or die "Cannot run stap: $!\n";
print $in $stap_src;
close $in;
sub usage {
return <<'_EOC_';
Usage:
tcp-accept-queue [optoins]
Options:
-a <args> Pass extra arguments to the stap utility.
-d Dump out the systemtap script source.
--distr Show queue length distribution only.
-h Print this usage.
--limit=<count> Exit when <count> queue overflowing issues are found.
(Default to 10)
--port=<port> Specify the listening port to be analyzed.
--time=<seconds> Time to wait before printing out the report and exiting
(Only meaningful with --distr)
Examples:
tcp-accept-queue --port 11211
tcp-accept-queue --port 6379 --limit 10 -a '-DMAXACTION=100000'
_EOC_
}