// Copyright 2009-2021 Intel Corporation
// SPDX-License-Identifier: Apache-2.0

#include "thread.h"
#include "sysinfo.h"
#include "string.h"

#include <iostream>
#if defined(__ARM_NEON)
#include "../simd/arm/emulation.h"
#else
#include <xmmintrin.h>
#endif

#if defined(PTHREADS_WIN32)
#pragma comment (lib, "pthreadVC.lib")
#endif

////////////////////////////////////////////////////////////////////////////////
/// Windows Platform
////////////////////////////////////////////////////////////////////////////////

#if defined(__WIN32__)

#define WIN32_LEAN_AND_MEAN
#include <windows.h>

namespace embree
{
  /*! set the affinity of a given thread */
  void setAffinity(HANDLE thread, ssize_t affinity)
  {
    typedef WORD (WINAPI *GetActiveProcessorGroupCountFunc)();
    typedef DWORD (WINAPI *GetActiveProcessorCountFunc)(WORD);
    typedef BOOL (WINAPI *SetThreadGroupAffinityFunc)(HANDLE, const GROUP_AFFINITY *, PGROUP_AFFINITY);
    typedef BOOL (WINAPI *SetThreadIdealProcessorExFunc)(HANDLE, PPROCESSOR_NUMBER, PPROCESSOR_NUMBER);
    HMODULE hlib = LoadLibrary("Kernel32");
    GetActiveProcessorGroupCountFunc pGetActiveProcessorGroupCount = (GetActiveProcessorGroupCountFunc)GetProcAddress(hlib, "GetActiveProcessorGroupCount");
    GetActiveProcessorCountFunc pGetActiveProcessorCount = (GetActiveProcessorCountFunc)GetProcAddress(hlib, "GetActiveProcessorCount");
    SetThreadGroupAffinityFunc pSetThreadGroupAffinity = (SetThreadGroupAffinityFunc)GetProcAddress(hlib, "SetThreadGroupAffinity");
    SetThreadIdealProcessorExFunc pSetThreadIdealProcessorEx = (SetThreadIdealProcessorExFunc)GetProcAddress(hlib, "SetThreadIdealProcessorEx");
    if (pGetActiveProcessorGroupCount && pGetActiveProcessorCount && pSetThreadGroupAffinity && pSetThreadIdealProcessorEx) 
    {
      int groups = pGetActiveProcessorGroupCount();
      int totalProcessors = 0, group = 0, number = 0;
      for (int i = 0; i<groups; i++) {
        int processors = pGetActiveProcessorCount(i);
        if (totalProcessors + processors > affinity) {
          group = i;
          number = (int)affinity - totalProcessors;
          break;
        }
        totalProcessors += processors;
      }
  
      GROUP_AFFINITY groupAffinity;
      groupAffinity.Group = (WORD)group;
      groupAffinity.Mask = (KAFFINITY)(uint64_t(1) << number);
      groupAffinity.Reserved[0] = 0;
      groupAffinity.Reserved[1] = 0;
      groupAffinity.Reserved[2] = 0;
      if (!pSetThreadGroupAffinity(thread, &groupAffinity, nullptr))
        WARNING("SetThreadGroupAffinity failed"); // on purpose only a warning
  
      PROCESSOR_NUMBER processorNumber;
      processorNumber.Group = group;
      processorNumber.Number = number;
      processorNumber.Reserved = 0;
      if (!pSetThreadIdealProcessorEx(thread, &processorNumber, nullptr))
        WARNING("SetThreadIdealProcessorEx failed"); // on purpose only a warning
    } 
    else 
    {
      if (!SetThreadAffinityMask(thread, DWORD_PTR(uint64_t(1) << affinity)))
        WARNING("SetThreadAffinityMask failed"); // on purpose only a warning
      if (SetThreadIdealProcessor(thread, (DWORD)affinity) == (DWORD)-1)
        WARNING("SetThreadIdealProcessor failed"); // on purpose only a warning
      }
  }

  /*! set affinity of the calling thread */
  void setAffinity(ssize_t affinity) {
    setAffinity(GetCurrentThread(), affinity);
  }

  struct ThreadStartupData 
  {
  public:
    ThreadStartupData (thread_func f, void* arg) 
      : f(f), arg(arg) {}
  public:
    thread_func f;
    void* arg;
  };

  DWORD WINAPI threadStartup(LPVOID ptr)
  {
    ThreadStartupData* parg = (ThreadStartupData*) ptr;
    _mm_setcsr(_mm_getcsr() | /*FTZ:*/ (1<<15) | /*DAZ:*/ (1<<6));
    parg->f(parg->arg);
    delete parg;
    return 0;
  }

#if !defined(PTHREADS_WIN32)

  /*! creates a hardware thread running on specific core */
  thread_t createThread(thread_func f, void* arg, size_t stack_size, ssize_t threadID)
  {
    HANDLE thread = CreateThread(nullptr, stack_size, threadStartup, new ThreadStartupData(f,arg), 0, nullptr);
    if (thread == nullptr) FATAL("CreateThread failed");
    if (threadID >= 0) setAffinity(thread, threadID);
    return thread_t(thread);
  }

  /*! the thread calling this function gets yielded */
  void yield() {
    SwitchToThread();
  }

  /*! waits until the given thread has terminated */
  void join(thread_t tid) {
    WaitForSingleObject(HANDLE(tid), INFINITE);
    CloseHandle(HANDLE(tid));
  }

  /*! destroy a hardware thread by its handle */
  void destroyThread(thread_t tid) {
    TerminateThread(HANDLE(tid),0);
    CloseHandle(HANDLE(tid));
  }

  /*! creates thread local storage */
  tls_t createTls() {
    return tls_t(size_t(TlsAlloc()));
  }

  /*! set the thread local storage pointer */
  void setTls(tls_t tls, void* const ptr) {
    TlsSetValue(DWORD(size_t(tls)), ptr);
  }

  /*! return the thread local storage pointer */
  void* getTls(tls_t tls) {
    return TlsGetValue(DWORD(size_t(tls)));
  }

  /*! destroys thread local storage identifier */
  void destroyTls(tls_t tls) {
    TlsFree(DWORD(size_t(tls)));
  }
#endif
}

#endif

////////////////////////////////////////////////////////////////////////////////
/// Linux Platform
////////////////////////////////////////////////////////////////////////////////

#if defined(__LINUX__)

#include <fstream>
#include <sstream>
#include <algorithm>

namespace embree
{
  static MutexSys mutex;
  static std::vector<size_t> threadIDs;
  
  /* changes thread ID mapping such that we first fill up all thread on one core */
  size_t mapThreadID(size_t threadID)
  {
    Lock<MutexSys> lock(mutex);
    
    if (threadIDs.size() == 0)
    {
      /* parse thread/CPU topology */
      for (size_t cpuID=0;;cpuID++)
      {
        std::fstream fs;
        std::string cpu = std::string("/sys/devices/system/cpu/cpu") + std::to_string((long long)cpuID) + std::string("/topology/thread_siblings_list");
        fs.open (cpu.c_str(), std::fstream::in);
        if (fs.fail()) break;

        int i;
        while (fs >> i) 
        {
          if (std::none_of(threadIDs.begin(),threadIDs.end(),[&] (int id) { return id == i; }))
            threadIDs.push_back(i);
          if (fs.peek() == ',') 
            fs.ignore();
        }
        fs.close();
      }

#if 0
      for (size_t i=0;i<threadIDs.size();i++)
        std::cout << i << " -> " << threadIDs[i] << std::endl;
#endif

      /* verify the mapping and do not use it if the mapping has errors */
      for (size_t i=0;i<threadIDs.size();i++) {
        for (size_t j=0;j<threadIDs.size();j++) {
          if (i != j && threadIDs[i] == threadIDs[j]) {
            threadIDs.clear();
          }
        }
      }
    }

    /* re-map threadIDs if mapping is available */
    size_t ID = threadID;
    if (threadID < threadIDs.size())
      ID = threadIDs[threadID];

    /* find correct thread to affinitize to */
    cpu_set_t set;
    if (pthread_getaffinity_np(pthread_self(), sizeof(set), &set) == 0)
    {
      for (int i=0, j=0; i<CPU_SETSIZE; i++)
      {
        if (!CPU_ISSET(i,&set)) continue;

        if (j == ID) {
          ID = i;
          break;
        }
        j++;
      }
    }

    return ID;
  }

  /*! set affinity of the calling thread */
  void setAffinity(ssize_t affinity)
  {
    cpu_set_t cset;
    CPU_ZERO(&cset);
    size_t threadID = mapThreadID(affinity);
    CPU_SET(threadID, &cset);

    pthread_setaffinity_np(pthread_self(), sizeof(cset), &cset);
  }
}
#endif

////////////////////////////////////////////////////////////////////////////////
/// FreeBSD Platform
////////////////////////////////////////////////////////////////////////////////

#if defined(__FreeBSD__)

#include <pthread_np.h>

namespace embree
{
  /*! set affinity of the calling thread */
  void setAffinity(ssize_t affinity)
  {
    cpuset_t cset;
    CPU_ZERO(&cset);
    CPU_SET(affinity, &cset);

    pthread_setaffinity_np(pthread_self(), sizeof(cset), &cset);
  }
}
#endif

////////////////////////////////////////////////////////////////////////////////
/// MacOSX Platform
////////////////////////////////////////////////////////////////////////////////

#if defined(__MACOSX__)

#include <mach/thread_act.h>
#include <mach/thread_policy.h>
#include <mach/mach_init.h>

namespace embree
{
  /*! set affinity of the calling thread */
  void setAffinity(ssize_t affinity)
  {
#if !defined(__ARM_NEON) // affinity seems not supported on M1 chip
    
    thread_affinity_policy ap;
    ap.affinity_tag = affinity;
    if (thread_policy_set(mach_thread_self(),THREAD_AFFINITY_POLICY,(thread_policy_t)&ap,THREAD_AFFINITY_POLICY_COUNT) != KERN_SUCCESS)
      WARNING("setting thread affinity failed"); // on purpose only a warning
    
#endif
  }
}
#endif

////////////////////////////////////////////////////////////////////////////////
/// Unix Platform
////////////////////////////////////////////////////////////////////////////////

#if defined(__UNIX__) || defined(PTHREADS_WIN32)

#include <pthread.h>
#include <sched.h>

#if defined(__USE_NUMA__)
#include <numa.h>
#endif

namespace embree
{
  struct ThreadStartupData 
  {
  public:
    ThreadStartupData (thread_func f, void* arg, int affinity) 
      : f(f), arg(arg), affinity(affinity) {}
  public: 
    thread_func f;
    void* arg;
    ssize_t affinity;
  };
  
  static void* threadStartup(ThreadStartupData* parg)
  {
    _mm_setcsr(_mm_getcsr() | /*FTZ:*/ (1<<15) | /*DAZ:*/ (1<<6));
    
    /*! Mac OS X does not support setting affinity at thread creation time */
#if defined(__MACOSX__)
    if (parg->affinity >= 0)
	setAffinity(parg->affinity);
#endif

    parg->f(parg->arg);
    delete parg;
    return nullptr;
  }

  /*! creates a hardware thread running on specific core */
  thread_t createThread(thread_func f, void* arg, size_t stack_size, ssize_t threadID)
  {
    /* set stack size */
    pthread_attr_t attr;
    pthread_attr_init(&attr);
    if (stack_size > 0) pthread_attr_setstacksize (&attr, stack_size);

    /* create thread */
    pthread_t* tid = new pthread_t;
    if (pthread_create(tid,&attr,(void*(*)(void*))threadStartup,new ThreadStartupData(f,arg,threadID)) != 0) {
      pthread_attr_destroy(&attr);
      delete tid; 
      FATAL("pthread_create failed");
    }
    pthread_attr_destroy(&attr);

    /* set affinity */
#if defined(__LINUX__)
    if (threadID >= 0) {
      cpu_set_t cset;
      CPU_ZERO(&cset);
      threadID = mapThreadID(threadID);
      CPU_SET(threadID, &cset);
      pthread_setaffinity_np(*tid, sizeof(cset), &cset);
    }
#elif defined(__FreeBSD__)
    if (threadID >= 0) {
      cpuset_t cset;
      CPU_ZERO(&cset);
      CPU_SET(threadID, &cset);
      pthread_setaffinity_np(*tid, sizeof(cset), &cset);
    }
#endif

    return thread_t(tid);
  }

  /*! the thread calling this function gets yielded */
  void yield() {
    sched_yield();
  }

  /*! waits until the given thread has terminated */
  void join(thread_t tid) {
    if (pthread_join(*(pthread_t*)tid, nullptr) != 0)
      FATAL("pthread_join failed");
    delete (pthread_t*)tid;
  }

  /*! destroy a hardware thread by its handle */
  void destroyThread(thread_t tid) {
    pthread_cancel(*(pthread_t*)tid);
    delete (pthread_t*)tid;
  }

  /*! creates thread local storage */
  tls_t createTls() 
  {
    pthread_key_t* key = new pthread_key_t;
    if (pthread_key_create(key,nullptr) != 0) {
      delete key;
      FATAL("pthread_key_create failed");
    }

    return tls_t(key);
  }

  /*! return the thread local storage pointer */
  void* getTls(tls_t tls) 
  {
    assert(tls);
    return pthread_getspecific(*(pthread_key_t*)tls);
  }

  /*! set the thread local storage pointer */
  void setTls(tls_t tls, void* const ptr) 
  {
    assert(tls);
    if (pthread_setspecific(*(pthread_key_t*)tls, ptr) != 0)
      FATAL("pthread_setspecific failed");
  }

  /*! destroys thread local storage identifier */
  void destroyTls(tls_t tls) 
  {
    assert(tls);
    if (pthread_key_delete(*(pthread_key_t*)tls) != 0)
      FATAL("pthread_key_delete failed");
    delete (pthread_key_t*)tls;
  }
}

#endif
