[Info-vax] Apache + mod_php performance

[Arne Vajhøj]

On 9/27/2024 9:18 AM, Craig A. Berry wrote:
> On 9/26/24 9:17 PM, Arne Vajhøj wrote:
>> On 9/26/2024 9:26 PM, Lawrence D'Oliveiro wrote:
>>> On Thu, 26 Sep 2024 21:20:38 -0400, Arne Vajhøj wrote:
>>>> A very quick search make me think that the mailbox is only used for
>>>> control not for data.
>>>
>>> Could still be a bottleneck, though.
>>
>> If it is only used for the parent to signal the child to terminate?
>>
>>>                                      That and the need for all the ASTs.
>>
>> Why should AST's be a problem?
>>
>> The "call this function when task is done" approach is
>> a very common design today. DEC was ahead of time with
>> that.
>>
>> And implementation wise then the AST's worked on VAX 700
>> series 45 years ago. Todays systems are extremely much
>> faster - maybe a factor 10000 faster.
> 
> There are some limitations around ASTs, especially when mixed with
> threads.  The definitive wizard article is here:
> 
> https://forum.vmssoftware.com/viewtopic.php?t=5198

Technically interesting.

But I don't think it is a big problem. To me it is either an event
driven model with single thread and everything non-blocking where
AST's make sense or a thread model with multiple threads and everything
blocking and no need for AST's.

> But I think your basic question is why Apache is slower than Tomcat,
> right?

Yes - it can be worded that way.

The question is why Apache (with PHP but that does not seem to matter)
is so slow.

Tomcat (with Quercus to provide PHP support) having much higher
numbers on the same system proves that it is not HW or VMS.

Also Apache on Windows on same CPU have much higher numbers
(number of threads have been bumped).

>         The only thing I can think of that hasn't already been mentioned
> is that Tomcat code is JIT-compiled, which is likely to be pretty good,
> optimized code, whereas Apache is probably either cross-compiled or
> native-compiled with an early enough field test compiler that there are
> no optimizations.

That is a possible explanation.

But the difference in numbers are crazy big.

Apache getting a static text file with 2 bytes: 22 req/sec

Tomcat with Quercus and PHP getting data out of a MySQL database on
Windows and outputting HTML: over 200 req/sec

Tomcat using JSP (which get triple compiled) getting data out of a MySQL
database on Windows (with db connection pool) and outputting HTML: over
600 req/sec.

My gut feeling is that cross-compilation may contribute to but not
fully explain the difference.

Arne