llvm/llvm/lib/Support/Unix/Threading.inc

//===- Unix/Threading.inc - Unix Threading Implementation ----- -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file provides the Unix specific implementation of Threading functions.
//
//===----------------------------------------------------------------------===//

#include "Unix.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/raw_ostream.h"

#if defined(__APPLE__)
#include <mach/mach_init.h>
#include <mach/mach_port.h>
#include <pthread/qos.h>
#include <sys/sysctl.h>
#include <sys/types.h>
#endif

#include <pthread.h>

#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
#include <pthread_np.h> // For pthread_getthreadid_np() / pthread_set_name_np()
#endif

#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
#include <errno.h>
#include <sys/cpuset.h>
#include <sys/sysctl.h>
#include <sys/user.h>
#include <unistd.h>
#endif

#if defined(__NetBSD__)
#include <lwp.h> // For _lwp_self()
#endif

#if defined(__OpenBSD__)
#include <unistd.h> // For getthrid()
#endif

#if defined(__linux__)
#include <sched.h>       // For sched_getaffinity
#include <sys/syscall.h> // For syscall codes
#include <unistd.h>      // For syscall()
#endif

#if defined(__HAIKU__)
#include <OS.h> // For B_OS_NAME_LENGTH
#endif

namespace llvm {
pthread_t
llvm_execute_on_thread_impl(void *(*ThreadFunc)(void *), void *Arg,
                            std::optional<unsigned> StackSizeInBytes) { … }

void llvm_thread_detach_impl(pthread_t Thread) { … }

void llvm_thread_join_impl(pthread_t Thread) { … }

pthread_t llvm_thread_get_id_impl(pthread_t Thread) { … }

pthread_t llvm_thread_get_current_id_impl() { … }

} // namespace llvm

uint64_t llvm::get_threadid() { … }

static constexpr uint32_t get_max_thread_name_length_impl() { … }

uint32_t llvm::get_max_thread_name_length() { … }

void llvm::set_thread_name(const Twine &Name) { … }

void llvm::get_thread_name(SmallVectorImpl<char> &Name) { … }

SetThreadPriorityResult llvm::set_thread_priority(ThreadPriority Priority) { … }

#include <thread>

static int computeHostNumHardwareThreads() { … }

void llvm::ThreadPoolStrategy::apply_thread_strategy(
    unsigned ThreadPoolNum) const { … }

llvm::BitVector llvm::get_thread_affinity_mask() { … }

unsigned llvm::get_cpus() { … }

#if defined(__linux__) && (defined(__i386__) || defined(__x86_64__))
// On Linux, the number of physical cores can be computed from /proc/cpuinfo,
// using the number of unique physical/core id pairs. The following
// implementation reads the /proc/cpuinfo format on an x86_64 system.
static int computeHostNumPhysicalCores() { … }
#elif (defined(__linux__) && defined(__s390x__)) || defined(_AIX)
static int computeHostNumPhysicalCores() {
  return sysconf(_SC_NPROCESSORS_ONLN);
}
#elif defined(__linux__) && !defined(__ANDROID__)
static int computeHostNumPhysicalCores() {
  cpu_set_t Affinity;
  if (sched_getaffinity(0, sizeof(Affinity), &Affinity) == 0)
    return CPU_COUNT(&Affinity);

  // The call to sched_getaffinity() may have failed because the Affinity
  // mask is too small for the number of CPU's on the system (i.e. the
  // system has more than 1024 CPUs). Allocate a mask large enough for
  // twice as many CPUs.
  cpu_set_t *DynAffinity;
  DynAffinity = CPU_ALLOC(2048);
  if (sched_getaffinity(0, CPU_ALLOC_SIZE(2048), DynAffinity) == 0) {
    int NumCPUs = CPU_COUNT(DynAffinity);
    CPU_FREE(DynAffinity);
    return NumCPUs;
  }
  return -1;
}
#elif defined(__APPLE__)
// Gets the number of *physical cores* on the machine.
static int computeHostNumPhysicalCores() {
  uint32_t count;
  size_t len = sizeof(count);
  sysctlbyname("hw.physicalcpu", &count, &len, NULL, 0);
  if (count < 1) {
    int nm[2];
    nm[0] = CTL_HW;
    nm[1] = HW_AVAILCPU;
    sysctl(nm, 2, &count, &len, NULL, 0);
    if (count < 1)
      return -1;
  }
  return count;
}
#elif defined(__MVS__)
static int computeHostNumPhysicalCores() {
  enum {
    // Byte offset of the pointer to the Communications Vector Table (CVT) in
    // the Prefixed Save Area (PSA). The table entry is a 31-bit pointer and
    // will be zero-extended to uintptr_t.
    FLCCVT = 16,
    // Byte offset of the pointer to the Common System Data Area (CSD) in the
    // CVT. The table entry is a 31-bit pointer and will be zero-extended to
    // uintptr_t.
    CVTCSD = 660,
    // Byte offset to the number of live CPs in the LPAR, stored as a signed
    // 32-bit value in the table.
    CSD_NUMBER_ONLINE_STANDARD_CPS = 264,
  };
  char *PSA = 0;
  char *CVT = reinterpret_cast<char *>(
      static_cast<uintptr_t>(reinterpret_cast<unsigned int &>(PSA[FLCCVT])));
  char *CSD = reinterpret_cast<char *>(
      static_cast<uintptr_t>(reinterpret_cast<unsigned int &>(CVT[CVTCSD])));
  return reinterpret_cast<int &>(CSD[CSD_NUMBER_ONLINE_STANDARD_CPS]);
}
#else
// On other systems, return -1 to indicate unknown.
static int computeHostNumPhysicalCores() { return -1; }
#endif

int llvm::get_physical_cores() { … }