[UPHPU] Why is require() slow? (SOLVED)

[Richard K Miller]

On Jan 9, 2008, at 6:12 PM, Richard K Miller wrote:

>
> On Jan 9, 2008, at 5:21 PM, Joseph Scott wrote:
>
>>
>> On Jan 9, 2008, at 4:39 PM, Richard K Miller wrote:
>>
>>> What would make require() slow? I installed APD[1] to profile a  
>>> slow running WordPress blog, and it said the 34 calls to require()  
>>> are taking 10.76 seconds to execute! Something must be wrong with  
>>> my server. This is a stock installation of WordPress on FreeBSD  
>>> and I have only one folder in my include_path.
>>
>>
>>
>> 10 seconds is way too long.  The front page of my WordPress blog  
>> (also on FreeBSD, yeah!) takes just over 1.1 seconds, with a single  
>> post page with 9 comments taking less than 0.7 seconds.  I'm also  
>> using Donncha's WP Super Cache plugin http://wordpress.org/extend/plugins/wp-super-cache/ 
>>  which helps.  I've also got APC http://pecl.php.net/package/APC  
>> running to reduce the parse/compile over head in PHP.
>>
>> My gut instinct on really slow loading pages like this is that  
>> there they have large content files (huge images, video embeds,  
>> etc.), but if your profiler indicates that it is the require() that  
>> is killing the performance I'm inclined to think it isn't a content  
>> issue.
>>
>> I'd look at the performance of a simple hello world PHP page and  
>> see what absolute lowest time your server push out a PHP file.   
>> From there add a simple require() and keep building it up until you  
>> can see a trend on where the performance is getting killed.
>
>
> I've generally been impressed with WordPress performance. I maintain  
> WordPress blogs for 30 people, none of which have caching plugins,  
> and none of them are this slow. What's funny is that this blog is  
> running on the same server as MediaWiki and MediaWiki isn't slow at  
> all. So I can't blame it on Wordpress nor can I blame it on the PHP/ 
> MySQL (I think.)
>
> I like your idea of adding more and more require()'s to a simple  
> file to see if that causes the slowdown. I'll try that.
>

I reran APD with the -tc flags (pprofp -tc) to show the (c)all tree  
and accumulated (t)ime and it led me directly to the problem. It  
wasn't require() after all:

Line 91 of wp-includes/cron.php does an fsockopen() call on itself.  
For some reason my server was not able to ping itself, so the  
fsockopen() call was timing out. After fixing my server, the slowness  
disappeared.