[Info-vax] Apache + mod_php performance

[Arne Vajhøj]

On 9/30/2024 9:36 PM, Lawrence D'Oliveiro wrote:
> On Mon, 30 Sep 2024 20:48:53 -0400, Arne Vajhøj wrote:
>> The world is moving from forking processes to starting threads.
> 
> That was tried in the 1990s -- threads for everything, even multithreaded
> GUIs. It was soon discovered that was not a great idea.

Practically all GUI's are multi-threaded.

At least a main thread and an event thread.

> Java, perhaps, embraced threads more than anybody: it made such heavy use
> of threads that it never even bothered to define a separate “lock” object
> type: instead, locking calls are built into the behaviour of every object!
>
> No other language copied that feature. Wonder why not?

There is no data in the object itself for it.

Java chose the syntax:

o.xxxx()

while .NET chose the syntax:

Monitor.Xxxx(o)

for this functionality.

Different syntax but same functionality.

I think the .NET syntax better explains what it does.

But it is just syntax.

>> As soon as Python are done getting rid of GIL then it will
>> join the thread party!
> 
> We understand better what to use threads for these days. They are good for
> CPU-intensive tasks that are parallelizable, not so much for anything
> else. That CPU-intensive stuff is not something you would tend to do in
> Python itself anyway: for high performance, you would delegate those tasks
> to “extension modules” written in C or such compiled languages. The usual
> flow within the extension code is
> 
> * Grab data from Python objects into some efficient native format
> * Free the GIL
> * Perform CPU-intensive tasks
> * Re-acquire the GIL
> * return results in Python objects
> 
> That third step takes full advantage of multithreading, without having to
> worry about the strictures of the Python GIL.

Threading is also a very convenient programming model for IO.

Blocking IO API's has some limits on scalability (like 500 threads
per CPU core).

But then there are various flavors of non-blocking API's.

And then there are blocking looking but not blocking under
the hood API's.

Arne