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ext/pcntl: cpu affinity improvements, targetting linux. #22883

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ext/pcntl: cpu affinity improvements, targetting linux.
devnexen Jul 24, 2026
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trigger build
devnexen Jul 25, 2026
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128 changes: 98 additions & 30 deletions ext/pcntl/pcntl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -57,53 +57,76 @@
#include <errno.h>
#if defined(HAVE_UNSHARE) || defined(HAVE_SCHED_SETAFFINITY) || defined(HAVE_SCHED_GETCPU)
#include <sched.h>
#if defined(__linux__) && defined(CPU_ALLOC)
#define PCNTL_CPUSET_DYNAMIC 1
typedef cpu_set_t *PCNTL_CPUSET_T;
#define PCNTL_CPUSET(mask) (mask)
#define PCNTL_CPUSET_SIZE(mask, sz) (sz)
#define PCNTL_CPU_ISSET(i, mask, sz) CPU_ISSET_S(i, sz, mask)
#define PCNTL_CPU_SET(i, mask, sz) CPU_SET_S(i, sz, mask)
#define PCNTL_CPU_ALLOC(mask, sz, maxcpus) \
do { \
(sz) = MAX(CPU_ALLOC_SIZE(maxcpus), sizeof(cpu_set_t)); \
(mask) = ecalloc(1, (sz)); \
} while (0)
#define PCNTL_CPU_DESTROY(mask) efree(mask)
#else
#if defined(__FreeBSD__)
#include <sys/types.h>
#include <sys/cpuset.h>
typedef cpuset_t cpu_set_t;
#endif
#define PCNTL_CPUSET(mask) &mask
#define PCNTL_CPUSET_SIZE(mask) sizeof(mask)
#define PCNTL_CPU_ISSET(i, mask) CPU_ISSET(i, &mask)
#define PCNTL_CPU_SET(i, mask) CPU_SET(i, &mask)
#define PCNTL_CPU_ZERO(mask) CPU_ZERO(&mask)
typedef cpu_set_t PCNTL_CPUSET_T;
#define PCNTL_CPUSET(mask) (&(mask))
#define PCNTL_CPUSET_SIZE(mask, sz) (sz)
#define PCNTL_CPU_ISSET(i, mask, sz) CPU_ISSET(i, &(mask))
#define PCNTL_CPU_SET(i, mask, sz) CPU_SET(i, &(mask))
#define PCNTL_CPU_ALLOC(mask, sz, maxcpus) \
do { \
CPU_ZERO(&(mask)); \
(sz) = sizeof(mask); \
} while (0)
#define PCNTL_CPU_DESTROY(mask) ((void)0)
#endif
#elif defined(__NetBSD__)
#include <sys/syscall.h>
#include <sched.h>
typedef cpuset_t *cpu_set_t;
typedef cpuset_t *PCNTL_CPUSET_T;
#define sched_getaffinity(p, c, m) syscall(SYS__sched_getaffinity, p, 0, c, m)
#define sched_setaffinity(p, c, m) syscall(SYS__sched_setaffinity, p, 0, c, m)
#define PCNTL_CPUSET(mask) mask
#define PCNTL_CPUSET_SIZE(mask) cpuset_size(mask)
#define PCNTL_CPU_ISSET(i, mask) cpuset_isset((cpuid_t)i, mask)
#define PCNTL_CPU_SET(i, mask) cpuset_set((cpuid_t)i, mask)
#define PCNTL_CPU_ZERO(mask) \
#define PCNTL_CPUSET(mask) (mask)
#define PCNTL_CPUSET_SIZE(mask, sz) (sz)
#define PCNTL_CPU_ISSET(i, mask, sz) cpuset_isset((cpuid_t)i, mask)
#define PCNTL_CPU_SET(i, mask, sz) cpuset_set((cpuid_t)i, mask)
#define PCNTL_CPU_ALLOC(mask, sz, maxcpus) \
do { \
mask = cpuset_create(); \
if (UNEXPECTED(!mask)) { \
php_error_docref(NULL, E_WARNING, "cpuset_create: Insufficient memory"); \
RETURN_FALSE; \
} \
cpuset_zero(mask); \
(sz) = cpuset_size(mask); \
} while(0)
#define PCNTL_CPU_DESTROY(mask) cpuset_destroy(mask)
#define HAVE_SCHED_SETAFFINITY 1
#elif defined(HAVE_PSET_BIND)
#include <sys/pset.h>
typedef psetid_t cpu_set_t;
#define sched_getaffinity(p, c, m) pset_bind(PS_QUERY, P_PID, p, &m)
#define sched_setaffinity(p, c, m) pset_bind(m, P_PID, (p <= 0 ? getpid() : p), NULL)
typedef psetid_t PCNTL_CPUSET_T;
#define sched_getaffinity(p, c, m) ((void)(c), pset_bind(PS_QUERY, P_PID, p, &m))
#define sched_setaffinity(p, c, m) ((void)(c), pset_bind(m, P_PID, (p <= 0 ? getpid() : p), NULL))
#define PCNTL_CPUSET(mask) mask
#define PCNTL_CPU_ISSET(i, mask) (pset_assign(PS_QUERY, (processorid_t)i, &query) == 0 && query == mask)
#define PCNTL_CPU_SET(i, mask) pset_assign(mask, (processorid_t)i, NULL)
#define PCNTL_CPU_ZERO(mask) \
#define PCNTL_CPUSET_SIZE(mask, sz) (sz)
#define PCNTL_CPU_ISSET(i, mask, sz) (pset_assign(PS_QUERY, (processorid_t)i, &query) == 0 && query == mask)
#define PCNTL_CPU_SET(i, mask, sz) pset_assign(mask, (processorid_t)i, NULL)
#define PCNTL_CPU_ALLOC(mask, sz, maxcpus) \
psetid_t query; \
do { \
if (UNEXPECTED(pset_create(&mask) != 0)) { \
php_error_docref(NULL, E_WARNING, "pset_create: %s", strerror(errno)); \
RETURN_FALSE; \
} \
(sz) = sizeof(mask); \
} while (0)
#define PCNTL_CPU_DESTROY(mask) \
do { \
Expand Down Expand Up @@ -1678,11 +1701,46 @@ PHP_FUNCTION(pcntl_setns)
#endif

#ifdef HAVE_SCHED_SETAFFINITY
static zend_long pcntl_cpu_count(void)
{
errno = 0;
zend_long maxcpus = sysconf(_SC_NPROCESSORS_CONF);
if (UNEXPECTED(maxcpus < 0)) {
PCNTL_G(last_error) = errno ? errno : EINVAL;
php_error_docref(NULL, E_WARNING, "Cannot determine the number of cpus");
}

return maxcpus;
}

#ifdef PCNTL_CPUSET_DYNAMIC
#define PCNTL_CPUSET_MAX_SIZE (1024 * 1024)

static bool pcntl_getaffinity(pid_t pid, PCNTL_CPUSET_T *mask, size_t *sz)
{
while (sched_getaffinity(pid, *sz, *mask) != 0) {
if (errno != EINVAL || *sz >= PCNTL_CPUSET_MAX_SIZE) {
return false;
}

efree(*mask);
*sz *= 2;
*mask = ecalloc(1, *sz);
}

return true;
}
#else
# define pcntl_getaffinity(pid, mask, sz) \
(sched_getaffinity(pid, PCNTL_CPUSET_SIZE(*(mask), *(sz)), PCNTL_CPUSET(*(mask))) == 0)
#endif

PHP_FUNCTION(pcntl_getcpuaffinity)
{
zend_long pid;
bool pid_is_null = 1;
cpu_set_t mask;
PCNTL_CPUSET_T mask;
size_t sz;

ZEND_PARSE_PARAMETERS_START(0, 1)
Z_PARAM_OPTIONAL
Expand All @@ -1691,10 +1749,15 @@ PHP_FUNCTION(pcntl_getcpuaffinity)

// 0 == getpid in this context, we're just saving a syscall
pid = pid_is_null ? 0 : pid;
zend_long maxcpus = pcntl_cpu_count();

PCNTL_CPU_ZERO(mask);
if (UNEXPECTED(maxcpus < 0)) {
RETURN_FALSE;
}

if (sched_getaffinity(pid, PCNTL_CPUSET_SIZE(mask), PCNTL_CPUSET(mask)) != 0) {
PCNTL_CPU_ALLOC(mask, sz, maxcpus);

if (!pcntl_getaffinity(pid, &mask, &sz)) {
PCNTL_CPU_DESTROY(mask);
PCNTL_G(last_error) = errno;
switch (errno) {
Expand All @@ -1714,12 +1777,11 @@ PHP_FUNCTION(pcntl_getcpuaffinity)
RETURN_FALSE;
}

zend_ulong maxcpus = (zend_ulong)sysconf(_SC_NPROCESSORS_CONF);
array_init(return_value);
zend_hash_real_init_packed(Z_ARRVAL_P(return_value));

for (zend_ulong i = 0; i < maxcpus; i ++) {
if (PCNTL_CPU_ISSET(i, mask)) {
for (zend_long i = 0; i < maxcpus; i ++) {
if (PCNTL_CPU_ISSET(i, mask, sz)) {
add_next_index_long(return_value, i);
}
}
Expand All @@ -1730,8 +1792,9 @@ PHP_FUNCTION(pcntl_setcpuaffinity)
{
zend_long pid;
bool pid_is_null = 1;
cpu_set_t mask;
PCNTL_CPUSET_T mask;
zval *hmask = NULL, *ncpu;
size_t sz;

ZEND_PARSE_PARAMETERS_START(0, 2)
Z_PARAM_OPTIONAL
Expand All @@ -1747,8 +1810,13 @@ PHP_FUNCTION(pcntl_setcpuaffinity)

// 0 == getpid in this context, we're just saving a syscall
pid = pid_is_null ? 0 : pid;
zend_long maxcpus = sysconf(_SC_NPROCESSORS_CONF);
PCNTL_CPU_ZERO(mask);
zend_long maxcpus = pcntl_cpu_count();

if (UNEXPECTED(maxcpus < 0)) {
RETURN_FALSE;
}

PCNTL_CPU_ALLOC(mask, sz, maxcpus);

ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(hmask), ncpu) {
ZVAL_DEREF(ncpu);
Expand All @@ -1773,17 +1841,17 @@ PHP_FUNCTION(pcntl_setcpuaffinity)
}

if (cpu < 0 || cpu >= maxcpus) {
zend_argument_value_error(2, "cpu id must be between 0 and " ZEND_ULONG_FMT " (" ZEND_LONG_FMT ")", maxcpus, cpu);
zend_argument_value_error(2, "cpu id must be between 0 and " ZEND_LONG_FMT " (" ZEND_LONG_FMT ")", maxcpus, cpu);
PCNTL_CPU_DESTROY(mask);
RETURN_THROWS();
}

if (!PCNTL_CPU_ISSET(cpu, mask)) {
PCNTL_CPU_SET(cpu, mask);
if (!PCNTL_CPU_ISSET(cpu, mask, sz)) {
PCNTL_CPU_SET(cpu, mask, sz);
}
} ZEND_HASH_FOREACH_END();

if (sched_setaffinity(pid, PCNTL_CPUSET_SIZE(mask), PCNTL_CPUSET(mask)) != 0) {
if (sched_setaffinity(pid, PCNTL_CPUSET_SIZE(mask, sz), PCNTL_CPUSET(mask)) != 0) {
PCNTL_CPU_DESTROY(mask);
PCNTL_G(last_error) = errno;
switch (errno) {
Expand Down
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