| File | /usr/lib/perl/5.10/Time/HiRes.pm |
| Statements Executed | 23 |
| Total Time | 0.0006854 seconds |
| Calls | P | F | Exclusive Time |
Inclusive Time |
Subroutine |
|---|---|---|---|---|---|
| 1 | 1 | 1 | 100µs | 215µs | Time::HiRes::import |
| 2 | 1 | 2 | 81µs | 81µs | Time::HiRes::bootstrap(xsub) |
| 3 | 2 | 2 | 29µs | 29µs | Time::HiRes::gettimeofday(xsub) |
| 0 | 0 | 0 | 0s | 0s | Time::HiRes::AUTOLOAD |
| 0 | 0 | 0 | 0s | 0s | Time::HiRes::BEGIN |
| 0 | 0 | 0 | 0s | 0s | Time::HiRes::__ANON__[:43] |
| 0 | 0 | 0 | 0s | 0s | Time::HiRes::tv_interval |
| Line | Stmts. | Exclusive Time | Avg. | Code |
|---|---|---|---|---|
| 1 | package Time::HiRes; | |||
| 2 | ||||
| 3 | 3 | 33µs | 11µs | use strict; # spent 8µs making 1 call to strict::import |
| 4 | 3 | 209µs | 70µs | use vars qw($VERSION $XS_VERSION @ISA @EXPORT @EXPORT_OK $AUTOLOAD); # spent 90µs making 1 call to vars::import |
| 5 | ||||
| 6 | 1 | 6µs | 6µs | require Exporter; |
| 7 | 1 | 800ns | 800ns | require DynaLoader; |
| 8 | ||||
| 9 | 1 | 12µs | 12µs | @ISA = qw(Exporter DynaLoader); |
| 10 | ||||
| 11 | 1 | 500ns | 500ns | @EXPORT = qw( ); |
| 12 | 1 | 8µs | 8µs | @EXPORT_OK = qw (usleep sleep ualarm alarm gettimeofday time tv_interval |
| 13 | getitimer setitimer nanosleep clock_gettime clock_getres | |||
| 14 | clock clock_nanosleep | |||
| 15 | CLOCK_HIGHRES CLOCK_MONOTONIC CLOCK_PROCESS_CPUTIME_ID | |||
| 16 | CLOCK_REALTIME CLOCK_SOFTTIME CLOCK_THREAD_CPUTIME_ID | |||
| 17 | CLOCK_TIMEOFDAY CLOCKS_PER_SEC | |||
| 18 | ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF ITIMER_REALPROF | |||
| 19 | TIMER_ABSTIME | |||
| 20 | d_usleep d_ualarm d_gettimeofday d_getitimer d_setitimer | |||
| 21 | d_nanosleep d_clock_gettime d_clock_getres | |||
| 22 | d_clock d_clock_nanosleep | |||
| 23 | stat | |||
| 24 | ); | |||
| 25 | ||||
| 26 | 1 | 500ns | 500ns | $VERSION = '1.9711'; |
| 27 | 1 | 400ns | 400ns | $XS_VERSION = $VERSION; |
| 28 | 1 | 28µs | 28µs | $VERSION = eval $VERSION; |
| 29 | ||||
| 30 | sub AUTOLOAD { | |||
| 31 | my $constname; | |||
| 32 | ($constname = $AUTOLOAD) =~ s/.*:://; | |||
| 33 | # print "AUTOLOAD: constname = $constname ($AUTOLOAD)\n"; | |||
| 34 | die "&Time::HiRes::constant not defined" if $constname eq 'constant'; | |||
| 35 | my ($error, $val) = constant($constname); | |||
| 36 | # print "AUTOLOAD: error = $error, val = $val\n"; | |||
| 37 | if ($error) { | |||
| 38 | my (undef,$file,$line) = caller; | |||
| 39 | die "$error at $file line $line.\n"; | |||
| 40 | } | |||
| 41 | { | |||
| 42 | 3 | 331µs | 110µs | no strict 'refs'; # spent 24µs making 1 call to strict::unimport |
| 43 | *$AUTOLOAD = sub { $val }; | |||
| 44 | } | |||
| 45 | goto &$AUTOLOAD; | |||
| 46 | } | |||
| 47 | ||||
| 48 | # spent 215µs (100+114) within Time::HiRes::import which was called
# once (100µs+114µs) by main::BEGIN at line 11 of /home/tamil/util/marc-moose/t/test-parsing | |||
| 49 | 4 | 19µs | 5µs | my $this = shift; |
| 50 | for my $i (@_) { | |||
| 51 | if (($i eq 'clock_getres' && !&d_clock_getres) || | |||
| 52 | ($i eq 'clock_gettime' && !&d_clock_gettime) || | |||
| 53 | ($i eq 'clock_nanosleep' && !&d_clock_nanosleep) || | |||
| 54 | ($i eq 'clock' && !&d_clock) || | |||
| 55 | ($i eq 'nanosleep' && !&d_nanosleep) || | |||
| 56 | ($i eq 'usleep' && !&d_usleep) || | |||
| 57 | ($i eq 'ualarm' && !&d_ualarm)) { | |||
| 58 | require Carp; | |||
| 59 | Carp::croak("Time::HiRes::$i(): unimplemented in this platform"); | |||
| 60 | } | |||
| 61 | } | |||
| 62 | Time::HiRes->export_to_level(1, $this, @_); # spent 26µs making 1 call to Exporter::export_to_level | |||
| 63 | } | |||
| 64 | ||||
| 65 | 1 | 19µs | 19µs | bootstrap Time::HiRes; # spent 367µs making 1 call to DynaLoader::bootstrap |
| 66 | ||||
| 67 | # Preloaded methods go here. | |||
| 68 | ||||
| 69 | sub tv_interval { | |||
| 70 | # probably could have been done in C | |||
| 71 | my ($a, $b) = @_; | |||
| 72 | $b = [gettimeofday()] unless defined($b); | |||
| 73 | (${$b}[0] - ${$a}[0]) + ((${$b}[1] - ${$a}[1]) / 1_000_000); | |||
| 74 | } | |||
| 75 | ||||
| 76 | # Autoload methods go after =cut, and are processed by the autosplit program. | |||
| 77 | ||||
| 78 | 1 | 19µs | 19µs | 1; |
| 79 | __END__ | |||
| 80 | ||||
| 81 | =head1 NAME | |||
| 82 | ||||
| 83 | Time::HiRes - High resolution alarm, sleep, gettimeofday, interval timers | |||
| 84 | ||||
| 85 | =head1 SYNOPSIS | |||
| 86 | ||||
| 87 | use Time::HiRes qw( usleep ualarm gettimeofday tv_interval nanosleep | |||
| 88 | clock_gettime clock_getres clock_nanosleep clock | |||
| 89 | stat ); | |||
| 90 | ||||
| 91 | usleep ($microseconds); | |||
| 92 | nanosleep ($nanoseconds); | |||
| 93 | ||||
| 94 | ualarm ($microseconds); | |||
| 95 | ualarm ($microseconds, $interval_microseconds); | |||
| 96 | ||||
| 97 | $t0 = [gettimeofday]; | |||
| 98 | ($seconds, $microseconds) = gettimeofday; | |||
| 99 | ||||
| 100 | $elapsed = tv_interval ( $t0, [$seconds, $microseconds]); | |||
| 101 | $elapsed = tv_interval ( $t0, [gettimeofday]); | |||
| 102 | $elapsed = tv_interval ( $t0 ); | |||
| 103 | ||||
| 104 | use Time::HiRes qw ( time alarm sleep ); | |||
| 105 | ||||
| 106 | $now_fractions = time; | |||
| 107 | sleep ($floating_seconds); | |||
| 108 | alarm ($floating_seconds); | |||
| 109 | alarm ($floating_seconds, $floating_interval); | |||
| 110 | ||||
| 111 | use Time::HiRes qw( setitimer getitimer ); | |||
| 112 | ||||
| 113 | setitimer ($which, $floating_seconds, $floating_interval ); | |||
| 114 | getitimer ($which); | |||
| 115 | ||||
| 116 | use Time::HiRes qw( clock_gettime clock_getres clock_nanosleep | |||
| 117 | ITIMER_REAL ITIMER_VIRTUAL ITIMER_PROF ITIMER_REALPROF ); | |||
| 118 | ||||
| 119 | $realtime = clock_gettime(CLOCK_REALTIME); | |||
| 120 | $resolution = clock_getres(CLOCK_REALTIME); | |||
| 121 | ||||
| 122 | clock_nanosleep(CLOCK_REALTIME, 1.5e9); | |||
| 123 | clock_nanosleep(CLOCK_REALTIME, time()*1e9 + 10e9, TIMER_ABSTIME); | |||
| 124 | ||||
| 125 | my $ticktock = clock(); | |||
| 126 | ||||
| 127 | use Time::HiRes qw( stat ); | |||
| 128 | ||||
| 129 | my @stat = stat("file"); | |||
| 130 | my @stat = stat(FH); | |||
| 131 | ||||
| 132 | =head1 DESCRIPTION | |||
| 133 | ||||
| 134 | The C<Time::HiRes> module implements a Perl interface to the | |||
| 135 | C<usleep>, C<nanosleep>, C<ualarm>, C<gettimeofday>, and | |||
| 136 | C<setitimer>/C<getitimer> system calls, in other words, high | |||
| 137 | resolution time and timers. See the L</EXAMPLES> section below and the | |||
| 138 | test scripts for usage; see your system documentation for the | |||
| 139 | description of the underlying C<nanosleep> or C<usleep>, C<ualarm>, | |||
| 140 | C<gettimeofday>, and C<setitimer>/C<getitimer> calls. | |||
| 141 | ||||
| 142 | If your system lacks C<gettimeofday()> or an emulation of it you don't | |||
| 143 | get C<gettimeofday()> or the one-argument form of C<tv_interval()>. | |||
| 144 | If your system lacks all of C<nanosleep()>, C<usleep()>, | |||
| 145 | C<select()>, and C<poll>, you don't get C<Time::HiRes::usleep()>, | |||
| 146 | C<Time::HiRes::nanosleep()>, or C<Time::HiRes::sleep()>. | |||
| 147 | If your system lacks both C<ualarm()> and C<setitimer()> you don't get | |||
| 148 | C<Time::HiRes::ualarm()> or C<Time::HiRes::alarm()>. | |||
| 149 | ||||
| 150 | If you try to import an unimplemented function in the C<use> statement | |||
| 151 | it will fail at compile time. | |||
| 152 | ||||
| 153 | If your subsecond sleeping is implemented with C<nanosleep()> instead | |||
| 154 | of C<usleep()>, you can mix subsecond sleeping with signals since | |||
| 155 | C<nanosleep()> does not use signals. This, however, is not portable, | |||
| 156 | and you should first check for the truth value of | |||
| 157 | C<&Time::HiRes::d_nanosleep> to see whether you have nanosleep, and | |||
| 158 | then carefully read your C<nanosleep()> C API documentation for any | |||
| 159 | peculiarities. | |||
| 160 | ||||
| 161 | If you are using C<nanosleep> for something else than mixing sleeping | |||
| 162 | with signals, give some thought to whether Perl is the tool you should | |||
| 163 | be using for work requiring nanosecond accuracies. | |||
| 164 | ||||
| 165 | Remember that unless you are working on a I<hard realtime> system, | |||
| 166 | any clocks and timers will be imprecise, especially so if you are working | |||
| 167 | in a pre-emptive multiuser system. Understand the difference between | |||
| 168 | I<wallclock time> and process time (in UNIX-like systems the sum of | |||
| 169 | I<user> and I<system> times). Any attempt to sleep for X seconds will | |||
| 170 | most probably end up sleeping B<more> than that, but don't be surpised | |||
| 171 | if you end up sleeping slightly B<less>. | |||
| 172 | ||||
| 173 | The following functions can be imported from this module. | |||
| 174 | No functions are exported by default. | |||
| 175 | ||||
| 176 | =over 4 | |||
| 177 | ||||
| 178 | =item gettimeofday () | |||
| 179 | ||||
| 180 | In array context returns a two-element array with the seconds and | |||
| 181 | microseconds since the epoch. In scalar context returns floating | |||
| 182 | seconds like C<Time::HiRes::time()> (see below). | |||
| 183 | ||||
| 184 | =item usleep ( $useconds ) | |||
| 185 | ||||
| 186 | Sleeps for the number of microseconds (millionths of a second) | |||
| 187 | specified. Returns the number of microseconds actually slept. | |||
| 188 | Can sleep for more than one second, unlike the C<usleep> system call. | |||
| 189 | Can also sleep for zero seconds, which often works like a I<thread yield>. | |||
| 190 | See also C<Time::HiRes::usleep()>, C<Time::HiRes::sleep()>, and | |||
| 191 | C<Time::HiRes::clock_nanosleep()>. | |||
| 192 | ||||
| 193 | Do not expect usleep() to be exact down to one microsecond. | |||
| 194 | ||||
| 195 | =item nanosleep ( $nanoseconds ) | |||
| 196 | ||||
| 197 | Sleeps for the number of nanoseconds (1e9ths of a second) specified. | |||
| 198 | Returns the number of nanoseconds actually slept (accurate only to | |||
| 199 | microseconds, the nearest thousand of them). Can sleep for more than | |||
| 200 | one second. Can also sleep for zero seconds, which often works like | |||
| 201 | a I<thread yield>. See also C<Time::HiRes::sleep()>, | |||
| 202 | C<Time::HiRes::usleep()>, and C<Time::HiRes::clock_nanosleep()>. | |||
| 203 | ||||
| 204 | Do not expect nanosleep() to be exact down to one nanosecond. | |||
| 205 | Getting even accuracy of one thousand nanoseconds is good. | |||
| 206 | ||||
| 207 | =item ualarm ( $useconds [, $interval_useconds ] ) | |||
| 208 | ||||
| 209 | Issues a C<ualarm> call; the C<$interval_useconds> is optional and | |||
| 210 | will be zero if unspecified, resulting in C<alarm>-like behaviour. | |||
| 211 | ||||
| 212 | ualarm(0) will cancel an outstanding ualarm(). | |||
| 213 | ||||
| 214 | Note that the interaction between alarms and sleeps is unspecified. | |||
| 215 | ||||
| 216 | =item tv_interval | |||
| 217 | ||||
| 218 | tv_interval ( $ref_to_gettimeofday [, $ref_to_later_gettimeofday] ) | |||
| 219 | ||||
| 220 | Returns the floating seconds between the two times, which should have | |||
| 221 | been returned by C<gettimeofday()>. If the second argument is omitted, | |||
| 222 | then the current time is used. | |||
| 223 | ||||
| 224 | =item time () | |||
| 225 | ||||
| 226 | Returns a floating seconds since the epoch. This function can be | |||
| 227 | imported, resulting in a nice drop-in replacement for the C<time> | |||
| 228 | provided with core Perl; see the L</EXAMPLES> below. | |||
| 229 | ||||
| 230 | B<NOTE 1>: This higher resolution timer can return values either less | |||
| 231 | or more than the core C<time()>, depending on whether your platform | |||
| 232 | rounds the higher resolution timer values up, down, or to the nearest second | |||
| 233 | to get the core C<time()>, but naturally the difference should be never | |||
| 234 | more than half a second. See also L</clock_getres>, if available | |||
| 235 | in your system. | |||
| 236 | ||||
| 237 | B<NOTE 2>: Since Sunday, September 9th, 2001 at 01:46:40 AM GMT, when | |||
| 238 | the C<time()> seconds since epoch rolled over to 1_000_000_000, the | |||
| 239 | default floating point format of Perl and the seconds since epoch have | |||
| 240 | conspired to produce an apparent bug: if you print the value of | |||
| 241 | C<Time::HiRes::time()> you seem to be getting only five decimals, not | |||
| 242 | six as promised (microseconds). Not to worry, the microseconds are | |||
| 243 | there (assuming your platform supports such granularity in the first | |||
| 244 | place). What is going on is that the default floating point format of | |||
| 245 | Perl only outputs 15 digits. In this case that means ten digits | |||
| 246 | before the decimal separator and five after. To see the microseconds | |||
| 247 | you can use either C<printf>/C<sprintf> with C<"%.6f">, or the | |||
| 248 | C<gettimeofday()> function in list context, which will give you the | |||
| 249 | seconds and microseconds as two separate values. | |||
| 250 | ||||
| 251 | =item sleep ( $floating_seconds ) | |||
| 252 | ||||
| 253 | Sleeps for the specified amount of seconds. Returns the number of | |||
| 254 | seconds actually slept (a floating point value). This function can | |||
| 255 | be imported, resulting in a nice drop-in replacement for the C<sleep> | |||
| 256 | provided with perl, see the L</EXAMPLES> below. | |||
| 257 | ||||
| 258 | Note that the interaction between alarms and sleeps is unspecified. | |||
| 259 | ||||
| 260 | =item alarm ( $floating_seconds [, $interval_floating_seconds ] ) | |||
| 261 | ||||
| 262 | The C<SIGALRM> signal is sent after the specified number of seconds. | |||
| 263 | Implemented using C<ualarm()>. The C<$interval_floating_seconds> argument | |||
| 264 | is optional and will be zero if unspecified, resulting in C<alarm()>-like | |||
| 265 | behaviour. This function can be imported, resulting in a nice drop-in | |||
| 266 | replacement for the C<alarm> provided with perl, see the L</EXAMPLES> below. | |||
| 267 | ||||
| 268 | B<NOTE 1>: With some combinations of operating systems and Perl | |||
| 269 | releases C<SIGALRM> restarts C<select()>, instead of interrupting it. | |||
| 270 | This means that an C<alarm()> followed by a C<select()> may together | |||
| 271 | take the sum of the times specified for the the C<alarm()> and the | |||
| 272 | C<select()>, not just the time of the C<alarm()>. | |||
| 273 | ||||
| 274 | Note that the interaction between alarms and sleeps is unspecified. | |||
| 275 | ||||
| 276 | =item setitimer ( $which, $floating_seconds [, $interval_floating_seconds ] ) | |||
| 277 | ||||
| 278 | Start up an interval timer: after a certain time, a signal ($which) arrives, | |||
| 279 | and more signals may keep arriving at certain intervals. To disable | |||
| 280 | an "itimer", use C<$floating_seconds> of zero. If the | |||
| 281 | C<$interval_floating_seconds> is set to zero (or unspecified), the | |||
| 282 | timer is disabled B<after> the next delivered signal. | |||
| 283 | ||||
| 284 | Use of interval timers may interfere with C<alarm()>, C<sleep()>, | |||
| 285 | and C<usleep()>. In standard-speak the "interaction is unspecified", | |||
| 286 | which means that I<anything> may happen: it may work, it may not. | |||
| 287 | ||||
| 288 | In scalar context, the remaining time in the timer is returned. | |||
| 289 | ||||
| 290 | In list context, both the remaining time and the interval are returned. | |||
| 291 | ||||
| 292 | There are usually three or four interval timers (signals) available: the | |||
| 293 | C<$which> can be C<ITIMER_REAL>, C<ITIMER_VIRTUAL>, C<ITIMER_PROF>, or | |||
| 294 | C<ITIMER_REALPROF>. Note that which ones are available depends: true | |||
| 295 | UNIX platforms usually have the first three, but (for example) Win32 | |||
| 296 | and Cygwin have only C<ITIMER_REAL>, and only Solaris seems to have | |||
| 297 | C<ITIMER_REALPROF> (which is used to profile multithreaded programs). | |||
| 298 | ||||
| 299 | C<ITIMER_REAL> results in C<alarm()>-like behaviour. Time is counted in | |||
| 300 | I<real time>; that is, wallclock time. C<SIGALRM> is delivered when | |||
| 301 | the timer expires. | |||
| 302 | ||||
| 303 | C<ITIMER_VIRTUAL> counts time in (process) I<virtual time>; that is, | |||
| 304 | only when the process is running. In multiprocessor/user/CPU systems | |||
| 305 | this may be more or less than real or wallclock time. (This time is | |||
| 306 | also known as the I<user time>.) C<SIGVTALRM> is delivered when the | |||
| 307 | timer expires. | |||
| 308 | ||||
| 309 | C<ITIMER_PROF> counts time when either the process virtual time or when | |||
| 310 | the operating system is running on behalf of the process (such as I/O). | |||
| 311 | (This time is also known as the I<system time>.) (The sum of user | |||
| 312 | time and system time is known as the I<CPU time>.) C<SIGPROF> is | |||
| 313 | delivered when the timer expires. C<SIGPROF> can interrupt system calls. | |||
| 314 | ||||
| 315 | The semantics of interval timers for multithreaded programs are | |||
| 316 | system-specific, and some systems may support additional interval | |||
| 317 | timers. For example, it is unspecified which thread gets the signals. | |||
| 318 | See your C<setitimer()> documentation. | |||
| 319 | ||||
| 320 | =item getitimer ( $which ) | |||
| 321 | ||||
| 322 | Return the remaining time in the interval timer specified by C<$which>. | |||
| 323 | ||||
| 324 | In scalar context, the remaining time is returned. | |||
| 325 | ||||
| 326 | In list context, both the remaining time and the interval are returned. | |||
| 327 | The interval is always what you put in using C<setitimer()>. | |||
| 328 | ||||
| 329 | =item clock_gettime ( $which ) | |||
| 330 | ||||
| 331 | Return as seconds the current value of the POSIX high resolution timer | |||
| 332 | specified by C<$which>. All implementations that support POSIX high | |||
| 333 | resolution timers are supposed to support at least the C<$which> value | |||
| 334 | of C<CLOCK_REALTIME>, which is supposed to return results close to the | |||
| 335 | results of C<gettimeofday>, or the number of seconds since 00:00:00:00 | |||
| 336 | January 1, 1970 Greenwich Mean Time (GMT). Do not assume that | |||
| 337 | CLOCK_REALTIME is zero, it might be one, or something else. | |||
| 338 | Another potentially useful (but not available everywhere) value is | |||
| 339 | C<CLOCK_MONOTONIC>, which guarantees a monotonically increasing time | |||
| 340 | value (unlike time(), which can be adjusted). See your system | |||
| 341 | documentation for other possibly supported values. | |||
| 342 | ||||
| 343 | =item clock_getres ( $which ) | |||
| 344 | ||||
| 345 | Return as seconds the resolution of the POSIX high resolution timer | |||
| 346 | specified by C<$which>. All implementations that support POSIX high | |||
| 347 | resolution timers are supposed to support at least the C<$which> value | |||
| 348 | of C<CLOCK_REALTIME>, see L</clock_gettime>. | |||
| 349 | ||||
| 350 | =item clock_nanosleep ( $which, $nanoseconds, $flags = 0) | |||
| 351 | ||||
| 352 | Sleeps for the number of nanoseconds (1e9ths of a second) specified. | |||
| 353 | Returns the number of nanoseconds actually slept. The $which is the | |||
| 354 | "clock id", as with clock_gettime() and clock_getres(). The flags | |||
| 355 | default to zero but C<TIMER_ABSTIME> can specified (must be exported | |||
| 356 | explicitly) which means that C<$nanoseconds> is not a time interval | |||
| 357 | (as is the default) but instead an absolute time. Can sleep for more | |||
| 358 | than one second. Can also sleep for zero seconds, which often works | |||
| 359 | like a I<thread yield>. See also C<Time::HiRes::sleep()>, | |||
| 360 | C<Time::HiRes::usleep()>, and C<Time::HiRes::nanosleep()>. | |||
| 361 | ||||
| 362 | Do not expect clock_nanosleep() to be exact down to one nanosecond. | |||
| 363 | Getting even accuracy of one thousand nanoseconds is good. | |||
| 364 | ||||
| 365 | =item clock() | |||
| 366 | ||||
| 367 | Return as seconds the I<process time> (user + system time) spent by | |||
| 368 | the process since the first call to clock() (the definition is B<not> | |||
| 369 | "since the start of the process", though if you are lucky these times | |||
| 370 | may be quite close to each other, depending on the system). What this | |||
| 371 | means is that you probably need to store the result of your first call | |||
| 372 | to clock(), and subtract that value from the following results of clock(). | |||
| 373 | ||||
| 374 | The time returned also includes the process times of the terminated | |||
| 375 | child processes for which wait() has been executed. This value is | |||
| 376 | somewhat like the second value returned by the times() of core Perl, | |||
| 377 | but not necessarily identical. Note that due to backward | |||
| 378 | compatibility limitations the returned value may wrap around at about | |||
| 379 | 2147 seconds or at about 36 minutes. | |||
| 380 | ||||
| 381 | =item stat | |||
| 382 | ||||
| 383 | =item stat FH | |||
| 384 | ||||
| 385 | =item stat EXPR | |||
| 386 | ||||
| 387 | As L<perlfunc/stat> but with the access/modify/change file timestamps | |||
| 388 | in subsecond resolution, if the operating system and the filesystem | |||
| 389 | both support such timestamps. To override the standard stat(): | |||
| 390 | ||||
| 391 | use Time::HiRes qw(stat); | |||
| 392 | ||||
| 393 | Test for the value of &Time::HiRes::d_hires_stat to find out whether | |||
| 394 | the operating system supports subsecond file timestamps: a value | |||
| 395 | larger than zero means yes. There are unfortunately no easy | |||
| 396 | ways to find out whether the filesystem supports such timestamps. | |||
| 397 | UNIX filesystems often do; NTFS does; FAT doesn't (FAT timestamp | |||
| 398 | granularity is B<two> seconds). | |||
| 399 | ||||
| 400 | A zero return value of &Time::HiRes::d_hires_stat means that | |||
| 401 | Time::HiRes::stat is a no-op passthrough for CORE::stat(), | |||
| 402 | and therefore the timestamps will stay integers. The same | |||
| 403 | thing will happen if the filesystem does not do subsecond timestamps, | |||
| 404 | even if the &Time::HiRes::d_hires_stat is non-zero. | |||
| 405 | ||||
| 406 | In any case do not expect nanosecond resolution, or even a microsecond | |||
| 407 | resolution. Also note that the modify/access timestamps might have | |||
| 408 | different resolutions, and that they need not be synchronized, e.g. | |||
| 409 | if the operations are | |||
| 410 | ||||
| 411 | write | |||
| 412 | stat # t1 | |||
| 413 | read | |||
| 414 | stat # t2 | |||
| 415 | ||||
| 416 | the access time stamp from t2 need not be greater-than the modify | |||
| 417 | time stamp from t1: it may be equal or I<less>. | |||
| 418 | ||||
| 419 | =back | |||
| 420 | ||||
| 421 | =head1 EXAMPLES | |||
| 422 | ||||
| 423 | use Time::HiRes qw(usleep ualarm gettimeofday tv_interval); | |||
| 424 | ||||
| 425 | $microseconds = 750_000; | |||
| 426 | usleep($microseconds); | |||
| 427 | ||||
| 428 | # signal alarm in 2.5s & every .1s thereafter | |||
| 429 | ualarm(2_500_000, 100_000); | |||
| 430 | # cancel that ualarm | |||
| 431 | ualarm(0); | |||
| 432 | ||||
| 433 | # get seconds and microseconds since the epoch | |||
| 434 | ($s, $usec) = gettimeofday(); | |||
| 435 | ||||
| 436 | # measure elapsed time | |||
| 437 | # (could also do by subtracting 2 gettimeofday return values) | |||
| 438 | $t0 = [gettimeofday]; | |||
| 439 | # do bunch of stuff here | |||
| 440 | $t1 = [gettimeofday]; | |||
| 441 | # do more stuff here | |||
| 442 | $t0_t1 = tv_interval $t0, $t1; | |||
| 443 | ||||
| 444 | $elapsed = tv_interval ($t0, [gettimeofday]); | |||
| 445 | $elapsed = tv_interval ($t0); # equivalent code | |||
| 446 | ||||
| 447 | # | |||
| 448 | # replacements for time, alarm and sleep that know about | |||
| 449 | # floating seconds | |||
| 450 | # | |||
| 451 | use Time::HiRes; | |||
| 452 | $now_fractions = Time::HiRes::time; | |||
| 453 | Time::HiRes::sleep (2.5); | |||
| 454 | Time::HiRes::alarm (10.6666666); | |||
| 455 | ||||
| 456 | use Time::HiRes qw ( time alarm sleep ); | |||
| 457 | $now_fractions = time; | |||
| 458 | sleep (2.5); | |||
| 459 | alarm (10.6666666); | |||
| 460 | ||||
| 461 | # Arm an interval timer to go off first at 10 seconds and | |||
| 462 | # after that every 2.5 seconds, in process virtual time | |||
| 463 | ||||
| 464 | use Time::HiRes qw ( setitimer ITIMER_VIRTUAL time ); | |||
| 465 | ||||
| 466 | $SIG{VTALRM} = sub { print time, "\n" }; | |||
| 467 | setitimer(ITIMER_VIRTUAL, 10, 2.5); | |||
| 468 | ||||
| 469 | use Time::HiRes qw( clock_gettime clock_getres CLOCK_REALTIME ); | |||
| 470 | # Read the POSIX high resolution timer. | |||
| 471 | my $high = clock_getres(CLOCK_REALTIME); | |||
| 472 | # But how accurate we can be, really? | |||
| 473 | my $reso = clock_getres(CLOCK_REALTIME); | |||
| 474 | ||||
| 475 | use Time::HiRes qw( clock_nanosleep TIMER_ABSTIME ); | |||
| 476 | clock_nanosleep(CLOCK_REALTIME, 1e6); | |||
| 477 | clock_nanosleep(CLOCK_REALTIME, 2e9, TIMER_ABSTIME); | |||
| 478 | ||||
| 479 | use Time::HiRes qw( clock ); | |||
| 480 | my $clock0 = clock(); | |||
| 481 | ... # Do something. | |||
| 482 | my $clock1 = clock(); | |||
| 483 | my $clockd = $clock1 - $clock0; | |||
| 484 | ||||
| 485 | use Time::HiRes qw( stat ); | |||
| 486 | my ($atime, $mtime, $ctime) = (stat("istics"))[8, 9, 10]; | |||
| 487 | ||||
| 488 | =head1 C API | |||
| 489 | ||||
| 490 | In addition to the perl API described above, a C API is available for | |||
| 491 | extension writers. The following C functions are available in the | |||
| 492 | modglobal hash: | |||
| 493 | ||||
| 494 | name C prototype | |||
| 495 | --------------- ---------------------- | |||
| 496 | Time::NVtime double (*)() | |||
| 497 | Time::U2time void (*)(pTHX_ UV ret[2]) | |||
| 498 | ||||
| 499 | Both functions return equivalent information (like C<gettimeofday>) | |||
| 500 | but with different representations. The names C<NVtime> and C<U2time> | |||
| 501 | were selected mainly because they are operating system independent. | |||
| 502 | (C<gettimeofday> is Unix-centric, though some platforms like Win32 and | |||
| 503 | VMS have emulations for it.) | |||
| 504 | ||||
| 505 | Here is an example of using C<NVtime> from C: | |||
| 506 | ||||
| 507 | double (*myNVtime)(); /* Returns -1 on failure. */ | |||
| 508 | SV **svp = hv_fetch(PL_modglobal, "Time::NVtime", 12, 0); | |||
| 509 | if (!svp) croak("Time::HiRes is required"); | |||
| 510 | if (!SvIOK(*svp)) croak("Time::NVtime isn't a function pointer"); | |||
| 511 | myNVtime = INT2PTR(double(*)(), SvIV(*svp)); | |||
| 512 | printf("The current time is: %f\n", (*myNVtime)()); | |||
| 513 | ||||
| 514 | =head1 DIAGNOSTICS | |||
| 515 | ||||
| 516 | =head2 useconds or interval more than ... | |||
| 517 | ||||
| 518 | In ualarm() you tried to use number of microseconds or interval (also | |||
| 519 | in microseconds) more than 1_000_000 and setitimer() is not available | |||
| 520 | in your system to emulate that case. | |||
| 521 | ||||
| 522 | =head2 negative time not invented yet | |||
| 523 | ||||
| 524 | You tried to use a negative time argument. | |||
| 525 | ||||
| 526 | =head2 internal error: useconds < 0 (unsigned ... signed ...) | |||
| 527 | ||||
| 528 | Something went horribly wrong-- the number of microseconds that cannot | |||
| 529 | become negative just became negative. Maybe your compiler is broken? | |||
| 530 | ||||
| 531 | =head1 CAVEATS | |||
| 532 | ||||
| 533 | Notice that the core C<time()> maybe rounding rather than truncating. | |||
| 534 | What this means is that the core C<time()> may be reporting the time | |||
| 535 | as one second later than C<gettimeofday()> and C<Time::HiRes::time()>. | |||
| 536 | ||||
| 537 | Adjusting the system clock (either manually or by services like ntp) | |||
| 538 | may cause problems, especially for long running programs that assume | |||
| 539 | a monotonously increasing time (note that all platforms do not adjust | |||
| 540 | time as gracefully as UNIX ntp does). For example in Win32 (and derived | |||
| 541 | platforms like Cygwin and MinGW) the Time::HiRes::time() may temporarily | |||
| 542 | drift off from the system clock (and the original time()) by up to 0.5 | |||
| 543 | seconds. Time::HiRes will notice this eventually and recalibrate. | |||
| 544 | Note that since Time::HiRes 1.77 the clock_gettime(CLOCK_MONOTONIC) | |||
| 545 | might help in this (in case your system supports CLOCK_MONOTONIC). | |||
| 546 | ||||
| 547 | =head1 SEE ALSO | |||
| 548 | ||||
| 549 | Perl modules L<BSD::Resource>, L<Time::TAI64>. | |||
| 550 | ||||
| 551 | Your system documentation for C<clock>, C<clock_gettime>, | |||
| 552 | C<clock_getres>, C<clock_nanosleep>, C<clock_settime>, C<getitimer>, | |||
| 553 | C<gettimeofday>, C<setitimer>, C<sleep>, C<stat>, C<ualarm>. | |||
| 554 | ||||
| 555 | =head1 AUTHORS | |||
| 556 | ||||
| 557 | D. Wegscheid <wegscd@whirlpool.com> | |||
| 558 | R. Schertler <roderick@argon.org> | |||
| 559 | J. Hietaniemi <jhi@iki.fi> | |||
| 560 | G. Aas <gisle@aas.no> | |||
| 561 | ||||
| 562 | =head1 COPYRIGHT AND LICENSE | |||
| 563 | ||||
| 564 | Copyright (c) 1996-2002 Douglas E. Wegscheid. All rights reserved. | |||
| 565 | ||||
| 566 | Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007 Jarkko Hietaniemi. All rights reserved. | |||
| 567 | ||||
| 568 | This program is free software; you can redistribute it and/or modify | |||
| 569 | it under the same terms as Perl itself. | |||
| 570 | ||||
| 571 | =cut | |||
# spent 81µs within Time::HiRes::bootstrap which was called
# once (81µs+0s) by DynaLoader::bootstrap at line 219 of /usr/lib/perl/5.10/DynaLoader.pm | ||||
# spent 29µs within Time::HiRes::gettimeofday which was called 2 times, avg 15µs/call:
# once (22µs+0s) by main::parse_with_marc_moose at line 82 of /home/tamil/util/marc-moose/t/test-parsing
# once (7µs+0s) by main::parse_with_marc_moose at line 86 of /home/tamil/util/marc-moose/t/test-parsing |