[PHP] How to reduce CPU usage in a cycle? [ag]
Hello!
I'm having a problem with my php script on my linux web server. In that
script there is a cycle with some math calculations (about ~30 steps), the
execution time is less 1 second, but the script loads the server CPU up to
90%...
I've optimized script already to the minimum math function, anyway, it still
overloads the CPU.
How can I reduce the CPU load? It seems that usleep() does not help much,
especially in Windows (it's not supported).
How can I give system a portion of time in the end of each step (I don't
mind if it will increase the job time)? Is there a solution for both Windows
and Linux?
For instance, in C++ under Windows I would do this:
do
{
[... math calculations ...]
while(::PeekMessage(message,NULL,0,0,PM_NOREMOVE))
if (!theApp.PumpMessage()) break;
} while(!quit);
This gives system to redraw screen, process any other events during long
cycles...
Is there similar approach in PHP for web server programming?
p.s. Would be nice to know other techniques to reduce CPU load ;)
Thank you!
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Re: [PHP] How to reduce CPU usage in a cycle? [ag]
Personally, I wouldn't worry about it unless it is actually interfering with other processes. The OS will give any process or thread 100% of the CPU if there is nothing else that needs the CPU. What does you context switching numbers look like? If there is a lot of context switching, then your processes or threads are getting kicked off the CPU before they can accomplish much. And that's a problem. The duration of your script is less than a second, so that's not really a long enough time have an affect on other parts of the system. Heck, it may even being completing within just a couple of time slices (the length of time the OS allows a process/thread to use the CPU). You could always adjust the priority level (nice value in Unix) of whatever PHP is running under (i.e. Apache). Although you should understand what you are doing if you are adjusting nice values. On Dec 11, 2003, at 10:03 AM, TauAlex wrote: Hello! I'm having a problem with my php script on my linux web server. In that script there is a cycle with some math calculations (about ~30 steps), the execution time is less 1 second, but the script loads the server CPU up to 90%... I've optimized script already to the minimum math function, anyway, it still overloads the CPU. How can I reduce the CPU load? It seems that usleep() does not help much, especially in Windows (it's not supported). How can I give system a portion of time in the end of each step (I don't mind if it will increase the job time)? Is there a solution for both Windows and Linux? -- Brent Baisley Systems Architect Landover Associates, Inc. Search Advisory Services for Advanced Technology Environments p: 212.759.6400/800.759.0577 -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] How to reduce CPU usage in a cycle? [ag]
Well have you tried to define one function to include the for all variables that require mt_rand()? Jas Brent Baisley wrote: Personally, I wouldn't worry about it unless it is actually interfering with other processes. The OS will give any process or thread 100% of the CPU if there is nothing else that needs the CPU. What does you context switching numbers look like? If there is a lot of context switching, then your processes or threads are getting kicked off the CPU before they can accomplish much. And that's a problem. The duration of your script is less than a second, so that's not really a long enough time have an affect on other parts of the system. Heck, it may even being completing within just a couple of time slices (the length of time the OS allows a process/thread to use the CPU). You could always adjust the priority level (nice value in Unix) of whatever PHP is running under (i.e. Apache). Although you should understand what you are doing if you are adjusting nice values. On Dec 11, 2003, at 10:03 AM, TauAlex wrote: Hello! I'm having a problem with my php script on my linux web server. In that script there is a cycle with some math calculations (about ~30 steps), the execution time is less 1 second, but the script loads the server CPU up to 90%... I've optimized script already to the minimum math function, anyway, it still overloads the CPU. How can I reduce the CPU load? It seems that usleep() does not help much, especially in Windows (it's not supported). How can I give system a portion of time in the end of each step (I don't mind if it will increase the job time)? Is there a solution for both Windows and Linux? -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] How to reduce CPU usage in a cycle? [ag]
ex.
?php
function rand($attack,$skills,$damage,$armor) {
$do = array($attack,$skills,$damage,$armor);
finish=false
while (!finish) {
$do = mt_rand(mktime(microtime(1,100)); }
while($do = list($attack,$skills,$damage,$armor)) {
calculate total damage for opponent }
}
?
I read that the use of mt_rand will produce the same results each time
the page is called with a certain number... so I would recommend using
microtime in conjunction with your mt_rand calls to ensure true random
numbers.
By throwing your vars into an array and looping through it applying your
random points deduction then listing the contents of the array (with new
values) it might improve cpu performance but then again. I am still
fairly new to php.
Jas
Jas wrote:
Well have you tried to define one function to include the for all
variables that require mt_rand()?
Jas
Brent Baisley wrote:
Personally, I wouldn't worry about it unless it is actually
interfering with other processes. The OS will give any process or
thread 100% of the CPU if there is nothing else that needs the CPU.
What does you context switching numbers look like? If there is a lot
of context switching, then your processes or threads are getting
kicked off the CPU before they can accomplish much. And that's a problem.
The duration of your script is less than a second, so that's not
really a long enough time have an affect on other parts of the system.
Heck, it may even being completing within just a couple of time slices
(the length of time the OS allows a process/thread to use the CPU).
You could always adjust the priority level (nice value in Unix) of
whatever PHP is running under (i.e. Apache). Although you should
understand what you are doing if you are adjusting nice values.
On Dec 11, 2003, at 10:03 AM, TauAlex wrote:
Hello!
I'm having a problem with my php script on my linux web server. In that
script there is a cycle with some math calculations (about ~30
steps), the
execution time is less 1 second, but the script loads the server CPU
up to
90%...
I've optimized script already to the minimum math function, anyway,
it still
overloads the CPU.
How can I reduce the CPU load? It seems that usleep() does not help
much,
especially in Windows (it's not supported).
How can I give system a portion of time in the end of each step (I don't
mind if it will increase the job time)? Is there a solution for both
Windows
and Linux?
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