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
|
/*
* pg_test_timing.c
* tests overhead of timing calls and their monotonicity: that
* they always move forward
*/
#include "postgres_fe.h"
#include <limits.h>
#include "getopt_long.h"
#include "portability/instr_time.h"
static const char *progname;
static unsigned int test_duration = 3;
static void handle_args(int argc, char *argv[]);
static uint64 test_timing(unsigned int duration);
static void output(uint64 loop_count);
/* record duration in powers of 2 microseconds */
long long int histogram[32];
int
main(int argc, char *argv[])
{
uint64 loop_count;
set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pg_test_timing"));
progname = get_progname(argv[0]);
handle_args(argc, argv);
loop_count = test_timing(test_duration);
output(loop_count);
return 0;
}
static void
handle_args(int argc, char *argv[])
{
static struct option long_options[] = {
{"duration", required_argument, NULL, 'd'},
{NULL, 0, NULL, 0}
};
int option; /* Command line option */
int optindex = 0; /* used by getopt_long */
unsigned long optval; /* used for option parsing */
char *endptr;
if (argc > 1)
{
if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
{
printf(_("Usage: %s [-d DURATION]\n"), progname);
exit(0);
}
if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
{
puts("pg_test_timing (PostgreSQL) " PG_VERSION);
exit(0);
}
}
while ((option = getopt_long(argc, argv, "d:",
long_options, &optindex)) != -1)
{
switch (option)
{
case 'd':
errno = 0;
optval = strtoul(optarg, &endptr, 10);
if (endptr == optarg || *endptr != '\0' ||
errno != 0 || optval != (unsigned int) optval)
{
fprintf(stderr, _("%s: invalid argument for option %s\n"),
progname, "--duration");
fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
exit(1);
}
test_duration = (unsigned int) optval;
if (test_duration == 0)
{
fprintf(stderr, _("%s: %s must be in range %u..%u\n"),
progname, "--duration", 1, UINT_MAX);
exit(1);
}
break;
default:
fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
progname);
exit(1);
break;
}
}
if (argc > optind)
{
fprintf(stderr,
_("%s: too many command-line arguments (first is \"%s\")\n"),
progname, argv[optind]);
fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
progname);
exit(1);
}
printf(ngettext("Testing timing overhead for %u second.\n",
"Testing timing overhead for %u seconds.\n",
test_duration),
test_duration);
}
static uint64
test_timing(unsigned int duration)
{
uint64 total_time;
int64 time_elapsed = 0;
uint64 loop_count = 0;
uint64 prev,
cur;
instr_time start_time,
end_time,
temp;
total_time = duration > 0 ? duration * INT64CONST(1000000) : 0;
INSTR_TIME_SET_CURRENT(start_time);
cur = INSTR_TIME_GET_MICROSEC(start_time);
while (time_elapsed < total_time)
{
int32 diff,
bits = 0;
prev = cur;
INSTR_TIME_SET_CURRENT(temp);
cur = INSTR_TIME_GET_MICROSEC(temp);
diff = cur - prev;
/* Did time go backwards? */
if (diff < 0)
{
fprintf(stderr, _("Detected clock going backwards in time.\n"));
fprintf(stderr, _("Time warp: %d ms\n"), diff);
exit(1);
}
/* What is the highest bit in the time diff? */
while (diff)
{
diff >>= 1;
bits++;
}
/* Update appropriate duration bucket */
histogram[bits]++;
loop_count++;
INSTR_TIME_SUBTRACT(temp, start_time);
time_elapsed = INSTR_TIME_GET_MICROSEC(temp);
}
INSTR_TIME_SET_CURRENT(end_time);
INSTR_TIME_SUBTRACT(end_time, start_time);
printf(_("Per loop time including overhead: %0.2f ns\n"),
INSTR_TIME_GET_DOUBLE(end_time) * 1e9 / loop_count);
return loop_count;
}
static void
output(uint64 loop_count)
{
int64 max_bit = 31,
i;
char *header1 = _("< us");
char *header2 = /* xgettext:no-c-format */ _("% of total");
char *header3 = _("count");
int len1 = strlen(header1);
int len2 = strlen(header2);
int len3 = strlen(header3);
/* find highest bit value */
while (max_bit > 0 && histogram[max_bit] == 0)
max_bit--;
printf(_("Histogram of timing durations:\n"));
printf("%*s %*s %*s\n",
Max(6, len1), header1,
Max(10, len2), header2,
Max(10, len3), header3);
for (i = 0; i <= max_bit; i++)
printf("%*ld %*.5f %*lld\n",
Max(6, len1), 1l << i,
Max(10, len2) - 1, (double) histogram[i] * 100 / loop_count,
Max(10, len3), histogram[i]);
}
|
