openmp/runtime/src/kmp_stats.cpp

/** @file kmp_stats.cpp
 * Statistics gathering and processing.
 */


//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.txt for details.
//
//===----------------------------------------------------------------------===//

#include "kmp.h"
#include "kmp_str.h"
#include "kmp_lock.h"
#include "kmp_stats.h"

#include <algorithm>
#include <sstream>
#include <iomanip>
#include <stdlib.h>                             // for atexit
#include <ctime>

#define STRINGIZE2(x) #x
#define STRINGIZE(x) STRINGIZE2(x)

#define expandName(name,flags,ignore)  {STRINGIZE(name),flags},
statInfo timeStat::timerInfo[] = {
    KMP_FOREACH_TIMER(expandName,0)
    {0,0}
};
const statInfo counter::counterInfo[] = {
    KMP_FOREACH_COUNTER(expandName,0)
    {0,0}
};
#undef expandName

#define expandName(ignore1,ignore2,ignore3)  {0.0,0.0,0.0},
kmp_stats_output_module::rgb_color kmp_stats_output_module::timerColorInfo[] = {
    KMP_FOREACH_TIMER(expandName,0)
    {0.0,0.0,0.0}
};
#undef expandName

const kmp_stats_output_module::rgb_color kmp_stats_output_module::globalColorArray[] = {
    {1.0, 0.0, 0.0}, // red
    {1.0, 0.6, 0.0}, // orange
    {1.0, 1.0, 0.0}, // yellow
    {0.0, 1.0, 0.0}, // green
    {0.0, 0.0, 1.0}, // blue
    {0.6, 0.2, 0.8}, // purple
    {1.0, 0.0, 1.0}, // magenta
    {0.0, 0.4, 0.2}, // dark green
    {1.0, 1.0, 0.6}, // light yellow
    {0.6, 0.4, 0.6}, // dirty purple
    {0.0, 1.0, 1.0}, // cyan
    {1.0, 0.4, 0.8}, // pink
    {0.5, 0.5, 0.5}, // grey
    {0.8, 0.7, 0.5}, // brown
    {0.6, 0.6, 1.0}, // light blue
    {1.0, 0.7, 0.5}, // peach
    {0.8, 0.5, 1.0}, // lavender
    {0.6, 0.0, 0.0}, // dark red
    {0.7, 0.6, 0.0}, // gold
    {0.0, 0.0, 0.0}  // black
};

// Ensure that the atexit handler only runs once.
static uint32_t statsPrinted = 0;

// output interface
static kmp_stats_output_module __kmp_stats_global_output;

/* ****************************************************** */
/* ************* statistic member functions ************* */

void statistic::addSample(double sample)
{
    double delta = sample - meanVal;

    sampleCount = sampleCount + 1;
    meanVal     = meanVal + delta/sampleCount;
    m2          = m2 + delta*(sample - meanVal);

    minVal = std::min(minVal, sample);
    maxVal = std::max(maxVal, sample);
}

statistic & statistic::operator+= (const statistic & other)
{
    if (sampleCount == 0)
    {
        *this = other;
        return *this;
    }

    uint64_t newSampleCount = sampleCount + other.sampleCount;
    double dnsc  = double(newSampleCount);
    double dsc   = double(sampleCount);
    double dscBydnsc = dsc/dnsc;
    double dosc  = double(other.sampleCount);
    double delta = other.meanVal - meanVal;

    // Try to order these calculations to avoid overflows.
    // If this were Fortran, then the compiler would not be able to re-order over brackets.
    // In C++ it may be legal to do that (we certainly hope it doesn't, and CC+ Programming Language 2nd edition
    // suggests it shouldn't, since it says that exploitation of associativity can only be made if the operation
    // really is associative (which floating addition isn't...)).
    meanVal     = meanVal*dscBydnsc + other.meanVal*(1-dscBydnsc);
    m2          = m2 + other.m2 + dscBydnsc*dosc*delta*delta;
    minVal      = std::min (minVal, other.minVal);
    maxVal      = std::max (maxVal, other.maxVal);
    sampleCount = newSampleCount;


    return *this;
}

void statistic::scale(double factor)
{
    minVal = minVal*factor;
    maxVal = maxVal*factor;
    meanVal= meanVal*factor;
    m2     = m2*factor*factor;
    return;
}

std::string statistic::format(char unit, bool total) const
{
    std::string result = formatSI(sampleCount,9,' ');

    if (sampleCount == 0)
    {
        result = result + std::string(", ") + formatSI(0.0, 9, unit);
        result = result + std::string(", ") + formatSI(0.0, 9, unit);
        result = result + std::string(", ") + formatSI(0.0, 9, unit);
        if (total)
            result = result + std::string(", ") + formatSI(0.0, 9, unit);
        result = result + std::string(", ") + formatSI(0.0, 9, unit);
    }
    else
    {
        result = result + std::string(", ") + formatSI(minVal,  9, unit);
        result = result + std::string(", ") + formatSI(meanVal, 9, unit);
        result = result + std::string(", ") + formatSI(maxVal,  9, unit);
        if (total)
            result = result + std::string(", ") + formatSI(meanVal*sampleCount, 9, unit);
        result = result + std::string(", ") + formatSI(getSD(), 9, unit);
    }
    return result;
}

/* ********************************************************** */
/* ************* explicitTimer member functions ************* */

void explicitTimer::start(timer_e timerEnumValue) {
    startTime = tsc_tick_count::now();
    totalPauseTime = 0;
    if(timeStat::logEvent(timerEnumValue)) {
        __kmp_stats_thread_ptr->incrementNestValue();
    }
    return;
}

void explicitTimer::stop(timer_e timerEnumValue) {
    if (startTime.getValue() == 0)
        return;

    tsc_tick_count finishTime = tsc_tick_count::now();

    //stat->addSample ((tsc_tick_count::now() - startTime).ticks());
    stat->addSample(((finishTime - startTime) - totalPauseTime).ticks());

    if(timeStat::logEvent(timerEnumValue)) {
        __kmp_stats_thread_ptr->push_event(startTime.getValue() - __kmp_stats_start_time.getValue(), finishTime.getValue() - __kmp_stats_start_time.getValue(), __kmp_stats_thread_ptr->getNestValue(), timerEnumValue);
        __kmp_stats_thread_ptr->decrementNestValue();
    }

    /* We accept the risk that we drop a sample because it really did start at t==0. */
    startTime = 0;
    return;
}

/* ************************************************************** */
/* ************* partitionedTimers member functions ************* */
partitionedTimers::partitionedTimers() {
    timer_stack.reserve(8);
}

// add a timer to this collection of partitioned timers.
void partitionedTimers::add_timer(explicit_timer_e timer_index, explicitTimer* timer_pointer) {
    KMP_DEBUG_ASSERT((int)timer_index < (int)EXPLICIT_TIMER_LAST+1);
    timers[timer_index] = timer_pointer;
}

// initialize the paritioned timers to an initial timer
void partitionedTimers::init(timerPair init_timer_pair) {
    KMP_DEBUG_ASSERT(this->timer_stack.size() == 0);
    timer_stack.push_back(init_timer_pair);
    timers[init_timer_pair.get_index()]->start(init_timer_pair.get_timer());
}

// stop/save the current timer, and start the new timer (timer_pair)
// There is a special condition where if the current timer is equal to
// the one you are trying to push, then it only manipulates the stack,
// and it won't stop/start the currently running timer.
void partitionedTimers::push(timerPair timer_pair) {
    // get the current timer
    // stop current timer
    // push new timer
    // start the new timer
    KMP_DEBUG_ASSERT(this->timer_stack.size() > 0);
    timerPair current_timer = timer_stack.back();
    timer_stack.push_back(timer_pair);
    if(current_timer != timer_pair) {
        timers[current_timer.get_index()]->pause();
        timers[timer_pair.get_index()]->start(timer_pair.get_timer());
    }
}

// stop/discard the current timer, and start the previously saved timer
void partitionedTimers::pop() {
    // get the current timer
    // stop current timer
    // pop current timer
    // get the new current timer and start it back up
    KMP_DEBUG_ASSERT(this->timer_stack.size() > 1);
    timerPair current_timer = timer_stack.back();
    timer_stack.pop_back();
    timerPair new_timer = timer_stack.back();
    if(current_timer != new_timer) {
        timers[current_timer.get_index()]->stop(current_timer.get_timer());
        timers[new_timer.get_index()]->resume();
    }
}

// Wind up all the currently running timers.
// This pops off all the timers from the stack and clears the stack
// After this is called, init() must be run again to initialize the
// stack of timers
void partitionedTimers::windup() {
    while(timer_stack.size() > 1) {
        this->pop();
    }
    if(timer_stack.size() > 0) {
        timerPair last_timer = timer_stack.back();
        timer_stack.pop_back();
        timers[last_timer.get_index()]->stop(last_timer.get_timer());
    }
}

/* ******************************************************************* */
/* ************* kmp_stats_event_vector member functions ************* */

void kmp_stats_event_vector::deallocate() {
    __kmp_free(events);
    internal_size = 0;
    allocated_size = 0;
    events = NULL;
}

// This function is for qsort() which requires the compare function to return
// either a negative number if event1 < event2, a positive number if event1 > event2
// or zero if event1 == event2.
// This sorts by start time (lowest to highest).
int compare_two_events(const void* event1, const void* event2) {
    kmp_stats_event* ev1 = (kmp_stats_event*)event1;
    kmp_stats_event* ev2 = (kmp_stats_event*)event2;

    if(ev1->getStart() < ev2->getStart()) return -1;
    else if(ev1->getStart() > ev2->getStart()) return 1;
    else return 0;
}

void kmp_stats_event_vector::sort() {
    qsort(events, internal_size, sizeof(kmp_stats_event), compare_two_events);
}

/* *********************************************************** */
/* ************* kmp_stats_list member functions ************* */

// returns a pointer to newly created stats node
kmp_stats_list* kmp_stats_list::push_back(int gtid) {
    kmp_stats_list* newnode = (kmp_stats_list*)__kmp_allocate(sizeof(kmp_stats_list));
    // placement new, only requires space and pointer and initializes (so __kmp_allocate instead of C++ new[] is used)
    new (newnode) kmp_stats_list();
    newnode->setGtid(gtid);
    newnode->prev = this->prev;
    newnode->next = this;
    newnode->prev->next = newnode;
    newnode->next->prev = newnode;
    return newnode;
}
void kmp_stats_list::deallocate() {
    kmp_stats_list* ptr = this->next;
    kmp_stats_list* delptr = this->next;
    while(ptr != this) {
        delptr = ptr;
        ptr=ptr->next;
        // placement new means we have to explicitly call destructor.
        delptr->_event_vector.deallocate();
        delptr->~kmp_stats_list();
        __kmp_free(delptr);
    }
}
kmp_stats_list::iterator kmp_stats_list::begin() {
    kmp_stats_list::iterator it;
    it.ptr = this->next;
    return it;
}
kmp_stats_list::iterator kmp_stats_list::end() {
    kmp_stats_list::iterator it;
    it.ptr = this;
    return it;
}
int kmp_stats_list::size() {
    int retval;
    kmp_stats_list::iterator it;
    for(retval=0, it=begin(); it!=end(); it++, retval++) {}
    return retval;
}

/* ********************************************************************* */
/* ************* kmp_stats_list::iterator member functions ************* */

kmp_stats_list::iterator::iterator() : ptr(NULL) {}
kmp_stats_list::iterator::~iterator() {}
kmp_stats_list::iterator kmp_stats_list::iterator::operator++() {
    this->ptr = this->ptr->next;
    return *this;
}
kmp_stats_list::iterator kmp_stats_list::iterator::operator++(int dummy) {
    this->ptr = this->ptr->next;
    return *this;
}
kmp_stats_list::iterator kmp_stats_list::iterator::operator--() {
    this->ptr = this->ptr->prev;
    return *this;
}
kmp_stats_list::iterator kmp_stats_list::iterator::operator--(int dummy) {
    this->ptr = this->ptr->prev;
    return *this;
}
bool kmp_stats_list::iterator::operator!=(const kmp_stats_list::iterator & rhs) {
   return this->ptr!=rhs.ptr;
}
bool kmp_stats_list::iterator::operator==(const kmp_stats_list::iterator & rhs) {
   return this->ptr==rhs.ptr;
}
kmp_stats_list* kmp_stats_list::iterator::operator*() const {
    return this->ptr;
}

/* *************************************************************** */
/* *************  kmp_stats_output_module functions ************** */

const char* kmp_stats_output_module::outputFileName = NULL;
const char* kmp_stats_output_module::eventsFileName = NULL;
const char* kmp_stats_output_module::plotFileName   = NULL;
int kmp_stats_output_module::printPerThreadFlag       = 0;
int kmp_stats_output_module::printPerThreadEventsFlag = 0;

// init() is called very near the beginning of execution time in the constructor of __kmp_stats_global_output
void kmp_stats_output_module::init()
{
    char * statsFileName  = getenv("KMP_STATS_FILE");
    eventsFileName        = getenv("KMP_STATS_EVENTS_FILE");
    plotFileName          = getenv("KMP_STATS_PLOT_FILE");
    char * threadStats    = getenv("KMP_STATS_THREADS");
    char * threadEvents   = getenv("KMP_STATS_EVENTS");

    // set the stats output filenames based on environment variables and defaults
    outputFileName = statsFileName;
    eventsFileName = eventsFileName ? eventsFileName : "events.dat";
    plotFileName   = plotFileName   ? plotFileName   : "events.plt";

    // set the flags based on environment variables matching: true, on, 1, .true. , .t. , yes
    printPerThreadFlag        = __kmp_str_match_true(threadStats);
    printPerThreadEventsFlag  = __kmp_str_match_true(threadEvents);

    if(printPerThreadEventsFlag) {
        // assigns a color to each timer for printing
        setupEventColors();
    } else {
        // will clear flag so that no event will be logged
        timeStat::clearEventFlags();
    }

    return;
}

void kmp_stats_output_module::setupEventColors() {
    int i;
    int globalColorIndex = 0;
    int numGlobalColors = sizeof(globalColorArray) / sizeof(rgb_color);
    for(i=0;i<TIMER_LAST;i++) {
        if(timeStat::logEvent((timer_e)i)) {
            timerColorInfo[i] = globalColorArray[globalColorIndex];
            globalColorIndex = (globalColorIndex+1)%numGlobalColors;
        }
    }
    return;
}

void kmp_stats_output_module::printTimerStats(FILE *statsOut, statistic const * theStats, statistic const * totalStats)
{
    fprintf (statsOut, "Timer,                      SampleCount,    Min,      Mean,       Max,     Total,        SD\n");
    for (timer_e s = timer_e(0); s<TIMER_LAST; s = timer_e(s+1)) {
        statistic const * stat = &theStats[s];
        char tag = timeStat::noUnits(s) ? ' ' : 'T';

        fprintf (statsOut, "%-28s, %s\n", timeStat::name(s), stat->format(tag, true).c_str());
    }
    // Also print the Total_ versions of times.
    for (timer_e s = timer_e(0); s<TIMER_LAST; s = timer_e(s+1)) {
        char tag = timeStat::noUnits(s) ? ' ' : 'T';
        if (totalStats && !timeStat::noTotal(s))
            fprintf(statsOut, "Total_%-22s, %s\n", timeStat::name(s), totalStats[s].format(tag, true).c_str());
    }
}

void kmp_stats_output_module::printCounterStats(FILE *statsOut, statistic const * theStats)
{
    fprintf (statsOut, "Counter,                 ThreadCount,    Min,      Mean,       Max,     Total,        SD\n");
    for (int s = 0; s<COUNTER_LAST; s++) {
        statistic const * stat = &theStats[s];
        fprintf (statsOut, "%-25s, %s\n", counter::name(counter_e(s)), stat->format(' ', true).c_str());
    }
}

void kmp_stats_output_module::printCounters(FILE * statsOut, counter const * theCounters)
{
    // We print all the counters even if they are zero.
    // That makes it easier to slice them into a spreadsheet if you need to.
    fprintf (statsOut, "\nCounter,                    Count\n");
    for (int c = 0; c<COUNTER_LAST; c++) {
        counter const * stat = &theCounters[c];
        fprintf (statsOut, "%-25s, %s\n", counter::name(counter_e(c)), formatSI(stat->getValue(), 9, ' ').c_str());
    }
}

void kmp_stats_output_module::printEvents(FILE* eventsOut, kmp_stats_event_vector* theEvents, int gtid) {
    // sort by start time before printing
    theEvents->sort();
    for (int i = 0; i < theEvents->size(); i++) {
        kmp_stats_event ev = theEvents->at(i);
        rgb_color color = getEventColor(ev.getTimerName());
        fprintf(eventsOut, "%d %lu %lu %1.1f rgb(%1.1f,%1.1f,%1.1f) %s\n",
                gtid,
                ev.getStart(),
                ev.getStop(),
                1.2 - (ev.getNestLevel() * 0.2),
                color.r, color.g, color.b,
                timeStat::name(ev.getTimerName())
               );
    }
    return;
}

void kmp_stats_output_module::windupExplicitTimers()
{
    // Wind up any explicit timers. We assume that it's fair at this point to just walk all the explcit timers in all threads
    // and say "it's over".
    // If the timer wasn't running, this won't record anything anyway.
    kmp_stats_list::iterator it;
    for(it = __kmp_stats_list.begin(); it != __kmp_stats_list.end(); it++) {
        kmp_stats_list* ptr = *it;
        ptr->getPartitionedTimers()->windup();
        for (int timer=0; timer<EXPLICIT_TIMER_LAST; timer++) {
            ptr->getExplicitTimer(explicit_timer_e(timer))->stop((timer_e)timer);
        }
    }
}

void kmp_stats_output_module::printPloticusFile() {
    int i;
    int size = __kmp_stats_list.size();
    FILE* plotOut = fopen(plotFileName, "w+");

    fprintf(plotOut, "#proc page\n"
                     "   pagesize: 15 10\n"
                     "   scale: 1.0\n\n");

    fprintf(plotOut, "#proc getdata\n"
                     "   file: %s\n\n",
                     eventsFileName);

    fprintf(plotOut, "#proc areadef\n"
                     "   title: OpenMP Sampling Timeline\n"
                     "   titledetails: align=center size=16\n"
                     "   rectangle: 1 1 13 9\n"
                     "   xautorange: datafield=2,3\n"
                     "   yautorange: -1 %d\n\n",
                     size);

    fprintf(plotOut, "#proc xaxis\n"
                     "   stubs: inc\n"
                     "   stubdetails: size=12\n"
                     "   label: Time (ticks)\n"
                     "   labeldetails: size=14\n\n");

    fprintf(plotOut, "#proc yaxis\n"
                     "   stubs: inc 1\n"
                     "   stubrange: 0 %d\n"
                     "   stubdetails: size=12\n"
                     "   label: Thread #\n"
                     "   labeldetails: size=14\n\n",
                     size-1);

    fprintf(plotOut, "#proc bars\n"
                     "   exactcolorfield: 5\n"
                     "   axis: x\n"
                     "   locfield: 1\n"
                     "   segmentfields: 2 3\n"
                     "   barwidthfield: 4\n\n");

    // create legend entries corresponding to the timer color
    for(i=0;i<TIMER_LAST;i++) {
        if(timeStat::logEvent((timer_e)i)) {
            rgb_color c = getEventColor((timer_e)i);
            fprintf(plotOut, "#proc legendentry\n"
                             "   sampletype: color\n"
                             "   label: %s\n"
                             "   details: rgb(%1.1f,%1.1f,%1.1f)\n\n",
                             timeStat::name((timer_e)i),
                             c.r, c.g, c.b);

        }
    }

    fprintf(plotOut, "#proc legend\n"
                     "   format: down\n"
                     "   location: max max\n\n");
    fclose(plotOut);
    return;
}

/*
 * Print some useful information about
 *    * the date and time this experiment ran.
 *    * the machine on which it ran.
 * We output all of this as stylised comments, though we may decide to parse some of it.
 */
void kmp_stats_output_module::printHeaderInfo(FILE * statsOut)
{
    std::time_t now = std::time(0);
    char buffer[40];
    char hostName[80];

    std::strftime(&buffer[0], sizeof(buffer), "%c", std::localtime(&now));
    fprintf (statsOut, "# Time of run: %s\n", &buffer[0]);
    if (gethostname(&hostName[0], sizeof(hostName)) == 0)
        fprintf (statsOut,"# Hostname: %s\n", &hostName[0]);
#if KMP_ARCH_X86 || KMP_ARCH_X86_64
    fprintf (statsOut, "# CPU:  %s\n", &__kmp_cpuinfo.name[0]);
    fprintf (statsOut, "# Family: %d, Model: %d, Stepping: %d\n", __kmp_cpuinfo.family, __kmp_cpuinfo.model, __kmp_cpuinfo.stepping);
    if (__kmp_cpuinfo.frequency == 0)
        fprintf (statsOut, "# Nominal frequency: Unknown\n");
    else
        fprintf (statsOut, "# Nominal frequency: %sz\n", formatSI(double(__kmp_cpuinfo.frequency),9,'H').c_str());
#endif
}

void kmp_stats_output_module::outputStats(const char* heading)
{
    // Stop all the explicit timers in all threads
    // Do this before declaring the local statistics because thay have constructors so will take time to create.
    windupExplicitTimers();

    statistic allStats[TIMER_LAST];
    statistic totalStats[TIMER_LAST];           /* Synthesized, cross threads versions of normal timer stats */
    statistic allCounters[COUNTER_LAST];

    FILE * statsOut = outputFileName ? fopen (outputFileName, "a+") : stderr;
    if (!statsOut)
        statsOut = stderr;

    FILE * eventsOut;
    if (eventPrintingEnabled()) {
        eventsOut = fopen(eventsFileName, "w+");
    }

    printHeaderInfo (statsOut);
    fprintf(statsOut, "%s\n",heading);
    // Accumulate across threads.
    kmp_stats_list::iterator it;
    for (it = __kmp_stats_list.begin(); it != __kmp_stats_list.end(); it++) {
        int t = (*it)->getGtid();
        // Output per thread stats if requested.
        if (printPerThreadFlag) {
            fprintf (statsOut, "Thread %d\n", t);
            printTimerStats (statsOut, (*it)->getTimers(), 0);
            printCounters   (statsOut, (*it)->getCounters());
            fprintf (statsOut,"\n");
        }
        // Output per thread events if requested.
        if (eventPrintingEnabled()) {
            kmp_stats_event_vector events = (*it)->getEventVector();
            printEvents(eventsOut, &events, t);
        }

        // Accumulate timers.
        for (timer_e s = timer_e(0); s<TIMER_LAST; s = timer_e(s+1)) {
            // See if we should ignore this timer when aggregating
            if ((timeStat::masterOnly(s) && (t != 0)) || // Timer is only valid on the master and this thread is a worker
                (timeStat::workerOnly(s) && (t == 0))    // Timer is only valid on a worker and this thread is the master
               )
            {
                continue;
            }

            statistic * threadStat = (*it)->getTimer(s);
            allStats[s] += *threadStat;

            // Add Total stats for timers that are valid in more than one thread
            if (!timeStat::noTotal(s))
                totalStats[s].addSample(threadStat->getTotal());
        }

        // Accumulate counters.
        for (counter_e c = counter_e(0); c<COUNTER_LAST; c = counter_e(c+1)) {
            if (counter::masterOnly(c) && t != 0)
                continue;
            allCounters[c].addSample ((*it)->getCounter(c)->getValue());
        }
    }

    if (eventPrintingEnabled()) {
        printPloticusFile();
        fclose(eventsOut);
    }

    fprintf (statsOut, "Aggregate for all threads\n");
    printTimerStats (statsOut, &allStats[0], &totalStats[0]);
    fprintf (statsOut, "\n");
    printCounterStats (statsOut, &allCounters[0]);

    if (statsOut != stderr)
        fclose(statsOut);
}

/* ************************************************** */
/* *************  exported C functions ************** */

// no name mangling for these functions, we want the c files to be able to get at these functions
extern "C" {

void __kmp_reset_stats()
{
    kmp_stats_list::iterator it;
    for(it = __kmp_stats_list.begin(); it != __kmp_stats_list.end(); it++) {
        timeStat * timers     = (*it)->getTimers();
        counter * counters    = (*it)->getCounters();
        explicitTimer * eTimers = (*it)->getExplicitTimers();

        for (int t = 0; t<TIMER_LAST; t++)
            timers[t].reset();

        for (int c = 0; c<COUNTER_LAST; c++)
            counters[c].reset();

        for (int t=0; t<EXPLICIT_TIMER_LAST; t++)
            eTimers[t].reset();

        // reset the event vector so all previous events are "erased"
        (*it)->resetEventVector();
    }
}

// This function will reset all stats and stop all threads' explicit timers if they haven't been stopped already.
void __kmp_output_stats(const char * heading)
{
    __kmp_stats_global_output.outputStats(heading);
    __kmp_reset_stats();
}

void __kmp_accumulate_stats_at_exit(void)
{
    // Only do this once.
    if (KMP_XCHG_FIXED32(&statsPrinted, 1) != 0)
        return;

    __kmp_output_stats("Statistics on exit");
}

void __kmp_stats_init(void)
{
}

} // extern "C"