One thing to keep in mind of course is that each zval incurs an overhead. $x = 1; requires 144 bytes of memory in total IIRC.
David
On 04.06.2011, at 23:38, Mike van Riel wrote:
> Dear Internals,
>
> During development of DocBlox I encountered a (for me) unusual situation
> with regards to memory usage.
>
> I hope you can shed some light on this for me as I do not understand.
>
> The situations is as follows:
>
> I have a php file containing about 53 KLOC (including whitespace and
> comments), which is about 2.1MB in size. When I execute the
> memory_get_peak_usage after running the token_get_all method on its
> content it reports that 232MB of RAM have been used in the process.
>
> I am having trouble understanding how 244003984B (232MB) RAM could be
> used.
>
> The following is what I have calculated:
> * 640.952B to start with (measured);
> * 2.1MB to load the file contents into memory using file_get_contents
> * 68 bytes for the resulting array
> * 68 bytes for each child array representing a token
> * 68 bytes for each element in a token array (which can be either 1 or
> 3, depending whether it is actually a token or literal)
> * 2.1MB in total for the string contents of the token literals /
> contents (equivalent to the byte size of the file)
>
> I have used the count method to retrieve the number of tokens (276697)
> and come to the following sum (everything is retrieved and calculated in
> bytes):
>
> 640952+2165950+68+(276697*68)+(276697*3*68)+2165950=80234436 = 76M
>
> This is a worst case formula where I assume that every token in the
> array consists of 3 elements.
>
> Based on this calculation I would be missing 156MB of memory; anybody
> know where that went?
>
> I used the following snippet of code for my tests:
>
> var_dump(memory_get_peak_usage());
> $tokens = token_get_all(file_get_contents('<PATH>'));
> var_dump(count($tokens));
> var_dump(memory_get_peak_usage());
>
> I hope this mail did not scare anyone ;)
>
> Kind regards,
>
> Mike van Riel
>
>
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