The page I am working on has a javascript function executed to print parts of the page. For some reason, printing in Safari, causes the window to somehow update. I say somehow, because it does not really refresh as in reload the page, but rather it starts the "rendering" of the page from start, i.e. scroll to top, flash animations start from 0, and so forth. The effect is reproduced by this fiddle: http://jsfiddle.net/fYmnB/ Clicking the print button and finishing or cancelling a print in Safari causes the screen to "go white" for a sec, which in my real website manifests itself as something "like" a reload. While running print button with, let's say, Firefox, just opens and closes the print dialogue without affecting the fiddle page in any way. Is there something with my way of calling the browsers print method that causes this, or how can it be explained - and preferably, avoided? P.S.: On my real site the same occurs with Chrome. In the ex
The basic idea, when executing a PHP script is in two steps :
ReplyDeleteFirst: the PHP code, written in plain-text, is compiled to opcodes
Then: those opcodes are executed.
When you have one PHP script, as long as it is not modified, the opcodes will always be the same ; so, doing the compilation phase each time that script is to be executed is kind of a waste of CPU-time.
To prevent that redundant-compilation, there are some opcode caching mechanism that you can use.
Once the PHP script has been compiled to opcodes, those will be kept in RAM -- and directly used from memory the next time the script is to be executed ; preventing the compilation from being done again and again.
The opcode cache which is used the most is APC - Alternative PHP Cache :
See on PECL to download the APC extension
And here's its manual
Once APC has been installed and configured properly, there is nothing you have to modify in your PHP code : APC will cache the opcodes, and that is all -- the process is totally invisible for your application.
But how to do it?
ReplyDeleteEasy.
First of all you have to do some profiling to be sure that code parsing being a bottleneck of your site, and all other obvious ones like unoptimized data storage, slow algorithms, data mining and network calls were optimized.
Easiest way to determine if you need opcode cache or not would be just putting this line at the very top of your most used page
$timer_start = microtime(1);
and this line at the very end:
echo "Generated in ".(round((microtime(1) - $timer_start),4))." sec.";
if time is more than 0.01, you have other things to optimize first, because you will notice no effect from opcode cache.