Login or Register to Ask a Question and Join Our Community


UNIX for Dummies Questions & Answers

Sleep less than 1 second

 
Thread Tools Search this Thread
Top Forums UNIX for Dummies Questions & Answers Sleep less than 1 second
# 8  
Old 08-24-2005
Quote:
Originally Posted by jim mcnamara
IT's not hard to measure the elapsed time:
Put Perderabo's code in a script, call it usleep.sh
Code:
time usleep.sh

will give you something like this:
Code:
kcsdev:/home/jmcnama> time usleep.sh

real    0m0.18s
user    0m0.03s
sys     0m0.05s

real is the elapsed time.

that's right, but... you have to consider the time it takes to load/initialize perl itself and how does that time relate to the actual 'sleep' time. Take a look here:
Code:
time perl -e 'select(undef,undef,undef,.001)'

real    0m0.030s
user    0m0.010s
sys     0m0.010s

The only real implementation would be a shell builtin, which ksh doesn't have. So perl is your best approximation.
# 9  
Old 08-24-2005
You're saying that the usleep doesn't "usleep" for just .1 seconds, right?

It does not matter in a multiuser, multiprocessing system. When a process "sleeps"
for any time slice, the time slice is the guaranteed minimum, not the max possible or even what normally will happen. The actual wait is dictated by the quantum (time slice), the base priority of the "waking up" process relative to anybody else wating for the cpu, and the length of the queue of processes waiting for the CPU.

So, if there were three same-priority processes ahead of you, the time slice is 100ms
(.1 second) and you wake up from sleep, the total sleep time could be as much as
the time you spent alseep plus the wait for three other processes to complete their quanta - in this case 100ms of sleep + (3 * 100ms) quantum slices = 400ms.
# 10  
Old 08-25-2005
Thanks vgersh99 and jim mcnamara for your great help. This is exactly what
i want and with the explanations you gave me i know how to use it.

Thanks a lot
 
Login or Register to Ask a Question

Previous Thread | Next Thread

9 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Sleep while i > 0

Hi, I have a script that runs a process at the beginning and I want to sleep/wait until this process is finished and then continue with the rest of the script. I am trying with this, but it is not working: process=`ps -ef | grep "proc_p01 -c" | grep -v grep | wc -l` if ; do sleep 10 done... (7 Replies)
Discussion started by: apenkov
7 Replies

2. UNIX for Dummies Questions & Answers

Sleep Until Query

Hi, I am a newbie in UNIX please help me develop code for below logic:-- I want my script to implement sleep until a specified time(date doesn't matter) ---------------------------------------- While currenttime > 14:00 and < 18:00 sleep end while run command exit... (9 Replies)
Discussion started by: kiitmale
9 Replies

3. UNIX for Dummies Questions & Answers

sleep infinity

This might be one of the dumbest questions you've got, but please bear with me: I am a UNIX beginner. I had an test today and I was asked the following question: Q. How do you put the terminal into sleep indefinitely? I didn't know the answer, but after I came home, I tried the following... (9 Replies)
Discussion started by: indyxandy
9 Replies

4. Shell Programming and Scripting

Wrapping 'sleep' with my 'resleep' function (Resettable sleep)

This is a very crude attempt in Bash at something that I needed but didn't seem to find in the 'sleep' command. However, I would like to be able to do it without the need for the temp file. Please go easy on me if this is already possible in some other way: How many times have you used the... (5 Replies)
Discussion started by: deckard
5 Replies

5. UNIX for Dummies Questions & Answers

sleep command

Hi All I have a requiremnt to run a script inside another script. here i am pulling the record count from the table in oracle.If record count is greater than 0 the script is executed.The scripts updates the count in the table and again the count is found out and the condition is checked and same... (3 Replies)
Discussion started by: dr46014
3 Replies

6. Shell Programming and Scripting

Sleep Command

I am in need of some help; think I have confused myself. Here is the issue I am faced with. The script log file was fine, the nohup.out file has tens of thousands of lines like illegal use of sleep: sleep seconds So I assume there is something with the seconds calculation in the script... (1 Reply)
Discussion started by: Glove
1 Replies

7. Programming

Sleep() not working

I have a function that quits a program when <ctrl>c is entered as per following code; void quitter (void) { clear (); mvprintw (QUITTER_ROW, QUITTER_COL, "Quitting..."); refresh (); sleep (15); endwin (); exit (1); }This function is called thus; signal (SIGINT, quitter); It... (2 Replies)
Discussion started by: enuenu
2 Replies

8. Shell Programming and Scripting

Sleep under one second

If I want a script to sleep for less than a second, would I use a decimal? In other words, if I wanted my script to sleep for 1/4 of a second, would I say, SLEEP .25 ?? (5 Replies)
Discussion started by: Scoogie
5 Replies

9. UNIX for Dummies Questions & Answers

sleep

what is the purpose of the sleep command? (5 Replies)
Discussion started by: Anna
5 Replies
Login or Register to Ask a Question