Asked  7 Months ago    Answers:  5   Viewed   36 times

Just wondering if anyone has information on what "costs" are associated with including a LARGE (600K or more) php file containing 100s of class files. Does it really make much difference in comparison to autoloading individual files that for instance searches across several directories before finding a match?

Would having APC caching on make this cost negligible?

 Answers

60

Basically, the cost of including one big file depend on your usecase. Let's say you have a large file with 200 classes.

If you only use 1 class, including the large file will be more expensive than including a small class file for that individual class.

If you use all 200 classes, including the large file will be significantly less expensive than including 200 small files.

Where the cutoff lies is really system dependent. I would imaging that it would be somewhere around the 50% mark (where if you're using less than 100 classes in any one request, autoload).

And using APC will likely shift the breakeven point closer to less classes (so without, 100 classes used might be the breakeven point, but with it might be at 50 classes used) since it makes the large single include much cheaper, but only lowers the overhead of each individual smaller include slightly.

The exact break-even points will be 100% system dependent (how fast is your disk I/O, how fast are your processors, how much memory, etc). So the only way to know for sure on your platform is to test.

However, more is at stake than raw performance. Maintainability will suffer with one large file since it's harder to work on multiple classes at the same time (tabs in an IDE become useless). I personally would keep all the classes in separate files and make my life as the developer easier rather than making one giant monstrosity of a file.

Now, if you have facebook traffic levels, it may be worth investigating further. But if you're not, I personally wouldn't worry about it...

Wednesday, March 31, 2021
 
pamelus
answered 7 Months ago
95

I have had a similar situation, but ultimately decided to implement with JSON and REST rather than the php-java bridge. The reduced complexity and greater re-use of services exposed as REST outweighed the need for better performance.

Saturday, May 29, 2021
 
Arman
answered 5 Months ago
13

If your columns are already defined, what about remove the column iterator?

Try something like this:

foreach ($activeSheet->getRowIterator() as $rkey => $row) {
    $rowIndex = $row->getRowIndex ();
    $parsedData[$rowIndex]['order'] = $activeSheet->getCell('A' . $rowIndex);
    $parsedData[$rowIndex]['ts']    = $activeSheet->getCell('B' . $rowIndex);
    $parsedData[$rowIndex]['summ']  = $activeSheet->getCell('C' . $rowIndex);
    .
    .
    .
}
Saturday, May 29, 2021
 
Raef
answered 5 Months ago
25

There are three parts to the cost of new:

  • Allocating the memory (may not be required if it's a value type)
  • Running the constructor (depending on what you're doing)
  • Garbage collection cost (again, this may not apply if it's a value type, depending on context)

It's hard to use C# idiomatically without ever creating any new objects in your main code... although I dare say it's feasible by reusing objects as heavily as possible. Try to get hold of some real devices, and see how your game performs.

I'd certainly agree that micro-optimization like this is usually to be avoided in programming, but it's more likely to be appropriate for game loops than elsewhere - as obviously games are very sensitive to even small pauses. It can be quite hard to judge the cost of using more objects though, as it's spread out over time due to GC costs.

The allocator and garbage collector is pretty good in .NET, although it's likely to be simpler on a device (Windows Phone 7, I assume)? In particular, I'm not sure whether the Compact Framework CLR (which is the one WP7 uses) has a generational GC.

Monday, August 9, 2021
 
Trott
answered 3 Months ago
33

A few pointers:

  • Debunking myths: proxies impact performance (have a look at the comments too)
  • Java theory and practice: Decorating with dynamic proxies
  • Benchmarking the cost of dynamic proxies
Saturday, September 4, 2021
 
Evan
answered 2 Months ago
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