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Date: Sat, 24 May 2025 20:48:39 +0200
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In-Reply-To: <bc1ec15125844c78a6aa23dce6148af9@danielkesselberg.de>
References: <bc1ec15125844c78a6aa23dce6148af9@danielkesselberg.de>
Subject: Re: [PHP-DEV] [RFC] Add num_available_processors
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From: rob@bottled.codes ("Rob Landers")

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On Sat, May 24, 2025, at 19:37, Daniel Kesselberg wrote:
> Hi everyone,
>=20
> I'm happy to share my first RFC :) It proposes adding a small function=20
> to retrieve the number of available processors; a feature that's=20
> commonly found in other programming languages and one that I believe=20
> would be a useful addition to PHP.
>=20
> The related PR has already received a bit of early traction, and now=20
> that the RFC is complete, I'm looking forward to your feedback!
>=20
> RFC: https://wiki.php.net/RFC/num_available_processors
> Patch: https://github.com/php/php-src/pull/11137
>=20
> Best
> Daniel
>=20

Looks good!

My main question is: what is this actually counting? In the RFC it menti=
ons "available processing units" ... which means, what? What counts as a=
 "processing unit"? Are we talking about CPU Threads/cores; NPU cores; T=
PM cores; clocks? GPS? GPU? ... a modern computer has many "processing u=
nits" for different purposes and workloads. I=E2=80=99m assuming this is=
 CPU Threads, not physical cores? I will refer to CPU Threads as "Logica=
l Cores" so we all don=E2=80=99t get confused since most of us here are =
programmers and saying "thread" has a different meaning.

Secondly, how is it counting "available"? If I assign PHP to a specific =
CPU affinity mask (say one logical core), will it return 1, or the total=
 number of logical cores available on my machine? I would expect it to b=
e 1, since PHP only has access to 1, but I can also see the logic in ret=
urning the total number.

=E2=80=94 Rob
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<!DOCTYPE html><html><head><title></title></head><body><div>On Sat, May =
24, 2025, at 19:37, Daniel Kesselberg wrote:</div><blockquote type=3D"ci=
te" id=3D"qt" style=3D""><div>Hi everyone,</div><div><br></div><div>I'm =
happy to share my first RFC :) It proposes adding a small function&nbsp;=
</div><div>to retrieve the number of available processors; a feature tha=
t's&nbsp;</div><div>commonly found in other programming languages and on=
e that I believe&nbsp;</div><div>would be a useful addition to PHP.</div=
><div><br></div><div>The related PR has already received a bit of early =
traction, and now&nbsp;</div><div>that the RFC is complete, I'm looking =
forward to your feedback!</div><div><br></div><div>RFC:&nbsp;<a href=3D"=
https://wiki.php.net/RFC/num_available_processors">https://wiki.php.net/=
RFC/num_available_processors</a></div><div>Patch:&nbsp;<a href=3D"https:=
//github.com/php/php-src/pull/11137">https://github.com/php/php-src/pull=
/11137</a></div><div><br></div><div>Best</div><div>Daniel</div><div><br>=
</div></blockquote><div><br></div><div>Looks good!</div><div><br></div><=
div>My main question is: what is this actually counting? In the RFC it m=
entions "available processing units" ... which means, what? What counts =
as a "processing unit"? Are we talking about CPU Threads/cores; NPU core=
s; TPM cores; clocks? GPS? GPU? ... a modern computer has many "processi=
ng units" for different purposes and workloads. I=E2=80=99m assuming thi=
s is CPU Threads, not physical cores? I will refer to CPU Threads as "Lo=
gical Cores" so we all don=E2=80=99t get confused since most of us here =
are programmers and saying "thread" has a different meaning.</div><div><=
br></div><div>Secondly, how is it counting "available"? If I assign PHP =
to a specific CPU affinity mask (say one logical core), will it return 1=
, or the total number of logical cores available on my machine? I would =
expect it to be 1, since PHP only has access to 1, but I can also see th=
e logic in returning the total number.</div><div><br></div><div id=3D"si=
g121229152">=E2=80=94 Rob</div></body></html>
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