[Info-vax] Apache + mod_php performance

[Arne Vajhøj]

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.

Arne