[Info-vax] Apache + mod_php performance

[Lawrence D'Oliveiro]

On Sun, 29 Sep 2024 20:02:59 -0400, Arne Vajhøj wrote:

> On 9/29/2024 7:43 PM, Lawrence D'Oliveiro wrote:
>>
>> On Sun, 29 Sep 2024 19:16:48 -0400, Arne Vajhøj wrote:
>>>
>>> On 9/29/2024 6:57 PM, Lawrence D'Oliveiro wrote:
>>>>
>>>> On Sun, 29 Sep 2024 10:46:12 -0400, Arne Vajhøj wrote:
>>>>>
>>>>> That is not how Apache prefork MPM works.
>>>>
>>>> If that’s not how it works, then how can you serve a client from more
>>>> than one member of the worker pool?
>>>
>>> A new request on a new connection goes to another worker. No problem.
>> 
>> But with keepalive, the request will come in on the existing
>> connection. So you have to dedicate a worker process to each
>> connection? That’s inefficient.
> 
> There is a reason that prefork MPM has been replaced by other MPM's.

No need. Threading inherently opens its own can of worms, which is why it 
is useful to keep the option of running multiple single-threaded 
processes.

>>>>> And I don't understand the "put all the client context into shared
>>>>> memory" either. Are you saying that if socket descriptors are put in
>>>>> shared memory then any process that map that memory can use those
>>>>> sockets????
>>>>
>>>> No, but the shared-memory context can contain an index into a table
>>>> of socket descriptors in private per-process memory. If the process
>>>> trying to server a client context does not actually have a socket
>>>> descriptor in the slot for that context, it can ask for one.
>>>
>>> I still can't follow the idea.
>>>
>>> Client X has a connection to server worker A. That means that A has
>>> index 77 in shared memory that points to the socket descriptor for the
>>> connection from X.
>>>
>>> Worker B wants to serve X as well and it get index 77 from shared
>>> memory. And then it does what?
>> 
>> Looks up its entry in its process-private copy of the array that
>> contains the socket descriptors, to see if it has its own valid fd for
>> that socket.
> 
> Yes. And if it does not then what?

Then it asks another process for a copy of that socket descriptor. Perhaps 
there is one overall connection-management process that accepts all new 
connections; if not, another worker that has that socket can pass it 
along.