[wp-hackers] Proposal for a function commenting convention

[Jacob]

You have to post your code.

In theory, it does make sense that comments will have a minor impact on 
performance, however it shouldn't have that much impact. The characters 
would still have to be parsed up to the point where a clear guess could 
be figured. Up to the point where it can be gathered that the line is 
whitespace it would have to devote some time to figuring out what to do 
before it can skip it and move on.

Much to the same reason why shorter variable names would have better 
performance than longer ones. I very much prefer longer variable names 
and also very much prefer documentation over having none.

Jacob Santos

Travis Snoozy wrote:
> On Sat, 13 Oct 2007 22:48:07 -0700, "Robin Adrianse"
> <robin.adr at gmail.com> wrote:
>
>   
>> I highly doubt it, but someone more knowledgeable about the PHP code
>> would know for sure.
>>
>> On 10/13/07, Matt <speedboxer at gmail.com> wrote:
>>     
>>> Ya... but... would documenting all (or most) of the functions make
>>> a huge impact on load times on the files since they'll be loaded
>>> with useless (in the executing sense) comments?
>>>       
>
> When in doubt, get some numbers. ;) I'm actually sort of surprised at
> the results I got.
>
> There does seem to be a distinct overhead involved with parsing
> comments. Specifically, I observed a 7.5% increase in the test load's
> average run time, and (assuming that the difference between the
> commented/non-commented times on the test load can be added to the
> non-commented average page generation time) a possible 12.2% increase
> in page generation time.
>
> My assumptions/setup are laid out as follows:
>
> * In wordpress 2.3, the string "function " comes up 2,425 times. A
> very conservative estimate would put every one of these instances as a
> function declaration that's part of the API.
>
> * Assuming each function takes an average of 1000 total comment
> characters to document (almost certainly a low number), that's 2,425,000
> characters of comments.
>
> * Comments were split into 1000-character blocks (multi-line) -- one
> giant multi-line comment took substantially longer to parse, but was
> inconsistent with the actual comment pattern that would be used.
>
> * All tests were performed on the same box, using
> PHP 5.2.4_p20070914-pl2-gentoo, and WordPress 2.3/MySQL 5.0.44/Apache
> 2.2.6 (where applicable).
>
>
> Here's the data I collected (using the "time" command):
>
>
> Running a file containing only the comments:
> real    0m0.153s	real    0m0.148s	real    0m0.143s
> user    0m0.083s	user    0m0.083s	user    0m0.080s
> sys     0m0.003s	sys     0m0.003s	sys     0m0.007s
>
> Average real: 0.148s
>
>
> Echoing zero to a million to /dev/null (with comments):
> real    0m1.575s	real    0m1.586s	real    0m1.578s
> user    0m1.373s	user    0m1.337s	user    0m1.340s
> sys     0m0.137s	sys     0m0.180s	sys     0m0.183s
>
> Average real: 1.580s
>
>
> Echoing zero to a million to /dev/null with no comments:
> real    0m1.467s	real    0m1.464s	real    0m1.465s
> user    0m1.253s	user    0m1.327s	user    0m1.323s
> sys     0m0.203s	sys     0m0.127s	sys     0m0.133s
>
> Average real: 1.465s
>
>
> Running an empty file (<?php?>):
> real    0m0.021s	real    0m0.023s	real    0m0.023s
> user    0m0.020s	user    0m0.020s	user    0m0.020s
> sys     0m0.000s	sys     0m0.003s	sys     0m0.003s
>
>
> Dumping the commented code file to /dev/null with cat:
> real    0m0.003s	real    0m0.006s	real    0m0.004s
> user    0m0.000s	user    0m0.000s	user    0m0.000s
> sys     0m0.003s	sys     0m0.007s	sys     0m0.003s
>
>
> For reference, these are the times it took to load the front page of my
> test blog (on the same machine as these other tests were performed):
> 1.076 seconds
> 0.810 seconds
> 0.948 seconds
>
> Average generation time: 0.945s
>
>
> And just for the curious...
> Running a file with one huge comment (~2.4 million chars):
>
> real    0m0.726s	real    0m0.731s	real    0m0.714s
> user    0m0.633s	user    0m0.653s	user    0m0.630s
> sys     0m0.017s	sys     0m0.000s	sys     0m0.023s
>
>
>
> 7-12% is a pretty big performance hit -- even a 4-5% improvement in
> script running time would still be worth considering optimization in
> many circumstances. Thus, it may be beneficial, if substantial
> commenting is added, to strip that commenting out in the distributed
> zipfile that's intended for deployment. Of course, we'll only know the
> actual impact once all those comments are there, but the ballpark
> figures would seem to indicate that it's worth keeping an eye on.
>
>
>