[Info-vax] Apache + mod_php performance

[Dave Froble]

On 9/30/2024 9:25 PM, Arne Vajhøj wrote:
> On 9/30/2024 9:10 PM, Dave Froble wrote:
>> On 9/30/2024 8:33 PM, Arne Vajhøj wrote:
>>> On 9/30/2024 8:24 PM, Lawrence D'Oliveiro wrote:
>>>> On Mon, 30 Sep 2024 19:50:38 -0400, Arne Vajhøj wrote:
>>>>> On 9/29/2024 11:15 PM, Lawrence D'Oliveiro wrote:
>>>>>> On Sun, 29 Sep 2024 22:34:04 -0400, Arne Vajhøj wrote:
>>>>>>> But I am pretty sure that it will not work on VMS.
>>>>>>
>>>>>> That’s what I figured. VMS, like Windows, really wants you to use
>>>>>> threads.
>>>>>
>>>>> For massive parallel processing on VMS then threads not
>>>>> processes is the way to go.
>>>>
>>>> Threads require shared memory, though. Processes allow you to have a mix
>>>> of shared and private data, plus the use of IPC mechanisms like message
>>>> passing. This makes for a looser coupling, which better suits the way
>>>> massively parallel systems are built.
>>>
>>> It is undeniable that multiple processes are more loosely coupled
>>> than multiple threads.
>>>
>>> But efficiency is a problem. VMS does not do fork. Process creation
>>> is expensive on VMS. None of that fancy moving descriptors over
>>> Unix socket stuff.
>>>
>>> VMS got plenty of methods for IPC. A solution with a fixed number
>>> of processes doing IPC between each other may work fine.
>>>
>>> But the concept of constantly starting new processes and killing
>>> old processes is not going to perform great.
>
>> Well, now, that is a rather bold statement.
>
> Sometimes I make such.
>
> :-)
>
>> Granted, starting up a new process involves some overhead.
>>
>> But it really depends upon the requirements.  The more use out of a process
>> once it is started, the better overall performance.  If a group of worker
>> processes is started once, then used for many tasks, then that overhead
>> happens only once.  Perhaps once a day, week, month, and even year.  There are
>> various communication methods available on VMS.
>>
>> In the end, it comes down to the requirements.  An engineer must evaluate the
>> task(s) and determine what methods will give adequate results.
>
> There are obviously a scale.
>
> But the Apache case is to start with 5 processes, start 145 new
> processes in a few seconds and then kill 140 again after maybe
> 30-45 seconds. And repeat.
>
> Arne
>
>
>

Perhaps the real problem is using a poorly designed application, regardless of 
how popular it might be?

-- 
David Froble                       Tel: 724-529-0450
Dave Froble Enterprises, Inc.      E-Mail: davef at tsoft-inc.com
DFE Ultralights, Inc.
170 Grimplin Road
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