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feat: add function num_cpus (formerly nproc) #11137

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feat: add function num_cpus (formerly nproc) #11137

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20 changes: 20 additions & 0 deletions ext/standard/basic_functions.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2578,3 +2578,23 @@ PHP_FUNCTION(sys_getloadavg)
}
/* }}} */
#endif

PHP_FUNCTION(num_available_processors)
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I'd just like to echo my feedback I just provided in PHP Internals here as well:

  • I think "processor" is a bit too ambiguous. I'd use "cpu_core" instead.
    Yes, technically that's not entirely accurate when hyper-threading is used, but in most cases it's not trivial to distinguish physical cores from logical cores anyway, and "cpu_cores" provides the most understandable abstraction for the vast majority of use cases: deciding how many parallel processes one should use for optimal use of the CPU.

  • Is it necessary to add "available" as a disambiguator?
    Are there future plans to add a function that provides the "total" or "unavailable" number of processors? If not, I'd just drop the "available" part.

  • From a quick search in php-src there doesn't seem to be any existing function name starting with num_. For the sake of consistency with the existing PHP functions, similar functionality in other languages, and following the principle of prefixing by primary concept, I suggest suffixing the function name with _count instead.

tl;dr: I'd like to respectfully propose the following function name instead:

cpu_core_count()

This helps with the semantic grouping of the function, and (to me, at least) gives a more succinct and understandable description of the function.

{
ZEND_PARSE_PARAMETERS_NONE();

#if defined(_SC_NPROCESSORS_ONLN)
int nprocs = sysconf(_SC_NPROCESSORS_ONLN);
if (nprocs > 0) {
RETURN_LONG(nprocs);
}
#elif defined _WIN32 && ! defined __CYGWIN__
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Suggested change
#elif defined _WIN32 && ! defined __CYGWIN__
#elif defined _WIN32

The check for cygwin is superfluous because _SC_NPROCESSORS_ONLN is defined: https://github.com/cygwin/cygwin/blob/2f43c4b625a1f72dc794144c799bfa4d9e812716/winsup/cygwin/sysconf.cc#L64

SYSTEM_INFO system_info;
GetSystemInfo (&system_info);
if (system_info.dwNumberOfProcessors > 0) {
RETURN_LONG(system_info.dwNumberOfProcessors);
}
#endif

RETURN_NULL();
}
2 changes: 2 additions & 0 deletions ext/standard/basic_functions.stub.php
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Expand Up @@ -3834,3 +3834,5 @@ function sapi_windows_set_ctrl_handler(?callable $handler, bool $add = true): bo

function sapi_windows_generate_ctrl_event(int $event, int $pid = 0): bool {}
#endif

function num_available_processors(): ?int {}
7 changes: 6 additions & 1 deletion ext/standard/basic_functions_arginfo.h
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16 changes: 16 additions & 0 deletions ext/standard/tests/general_functions/num_available_processors.phpt
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@@ -0,0 +1,16 @@
--TEST--
num_available_processors() tests
--SKIPIF--
<?php
if (!function_exists("num_available_processors")) die("skip");
?>
--FILE--
<?php

var_dump(num_available_processors());

echo "Done\n";
?>
--EXPECTF--
int(%d)
Done