http://www.tcl.tk/man/tcl8.5/TclCmd/time.htm 



Executes ''script'' and reports how long it takes per iteration (if ''iterations'' is absent, only one iteration is used). From 8.5, the report has sub-microsecond resolution (with accuracy depending on the OS's available timers).

<<discussion>>
** Description **
Does anyone have some examples of using [Tcl]'s time command?
'''`time`''' executes ''script'' one time, or optionally, ''iterations'' times,
time {myCommand $arg1 $arg2} 1000
 time {myCommand $arg1 $arg2} 1000

will run the specified command, with substitutions performed, 1000 times, and finally return a list like this:

The higher you give the factor, the more precise the measurement will be, but of course take proportional time - so best start with small values, and increase until it feels too slow.

See [How to measure Performance] for additional info - but no obvious examples.
More iterations increase the precision of the returned value, at the cost of


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Also another use of the word ''time'' is as a network protocol for the transmission of time data - see RFC868 [http://www.faqs.org/rfcs/rfc868.html]
[NTP] is a more sophisticated protocol, but the time protocol does a simple job simply.

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In yet another different use of the word '''time''', [LV] asks "Has anyone written a ''time'' chooser similar to the date chooser widgets written elsewhere on the Wiki?" Larry refers to [A little date chooser] and [An i15d date chooser].
You can measure the runtime of a lengthy script with the following pattern:
You might like to check out: [timeentry] and [timefield].
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set t0 [clock clicks -millisec]
 set t0 [clock clicks -millisec]
 ...
 ...
 puts stderr "[expr ([clock clicks -millisec]-$t0)/1000.] sec" ;# RS

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Even when you're not interested in the timing, you can use [time] as a simple control structure for loops:
proc measure args {
 time {puts Hello} 5


for {set i 0} {$i<5} {incr i} {puts Hello}
 for {set i 0} {$i<5} {incr i} {puts Hello}


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[LV] Sometimes users ask how to get a tcl program's time in terms of real/user/system, similar to how they would use the ksh built in time command.

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<<discussion>>
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