aaron/ispc
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Modify rt example to also do a set of runs with tasks + SPMD together.

Browse Source
This commit is contained in:
Matt Pharr
2011-08-17 13:14:32 +01:00
parent d7662b3eb9
commit 60bdf1ef8a
7 changed files with 643 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
examples/rt/Makefile
View File

@@ -1,4 +1,16 @@
ARCH = $(shell uname)
TASK_CXX=tasks_pthreads.cpp
TASK_LIB=-lpthread
ifeq ($(ARCH), Darwin)
TASK_CXX=tasks_gcd.cpp
TASK_LIB=
endif
TASK_OBJ=$(addprefix objs/, $(TASK_CXX:.cpp=.o))
CXX=g++ -m64
CXXFLAGS=-Iobjs/ -O3 -Wall
ISPC=ispc
@@ -14,11 +26,13 @@ dirs:
clean:
/bin/rm -rf objs *~ rt
rt: dirs objs/rt.o objs/rt_serial.o objs/rt_ispc.o
$(CXX) $(CXXFLAGS) -o $@ objs/rt.o objs/rt_ispc.o objs/rt_serial.o -lm
rt: dirs objs/rt.o objs/rt_serial.o objs/rt_ispc.o $(TASK_OBJ)
$(CXX) $(CXXFLAGS) -o $@ objs/rt.o objs/rt_ispc.o objs/rt_serial.o $(TASK_OBJ) -lm $(TASK_LIB)
objs/%.o: %.cpp objs/rt_ispc.h
objs/%.o: %.cpp
$(CXX) $< $(CXXFLAGS) -c -o $@
objs/rt.o: objs/rt_ispc.h
objs/%_ispc.h objs/%_ispc.o: %.ispc
$(ISPC) $(ISPCFLAGS) $< -o objs/$*_ispc.o -h objs/$*_ispc.h

41
examples/rt/rt.cpp
View File

@@ -134,6 +134,9 @@ int main(int argc, char *argv[]) {
ensureTargetISAIsSupported();
extern void TasksInit();
TasksInit();
#define READ(var, n) \
if (fread(&(var), sizeof(var), n, f) != (unsigned int)n) { \
fprintf(stderr, "Unexpected EOF reading scene file\n"); \
@@ -215,7 +218,7 @@ int main(int argc, char *argv[]) {
}
fclose(f);
// round image resolution up to multiple of 4 to makethings easy for
// round image resolution up to multiple of 4 to make things easy for
// the code that assigns pixels to ispc program instances
height = (height + 3) & ~3;
width = (width + 3) & ~3;
@@ -226,19 +229,42 @@ int main(int argc, char *argv[]) {
float *image = new float[width*height];
//
// Run 3 iterations with ispc, record the minimum time
// Run 3 iterations with ispc + 1 core, record the minimum time
//
double minTimeISPC = 1e30;
for (int i = 0; i < 3; ++i) {
reset_and_start_timer();
raytrace(width, height, raster2camera, camera2world,
image, id, nodes, triangles);
raytrace_ispc(width, height, raster2camera, camera2world,
image, id, nodes, triangles);
double dt = get_elapsed_mcycles();
minTimeISPC = std::min(dt, minTimeISPC);
}
printf("[rt ispc]:\t\t\t[%.3f] million cycles for %d x %d image\n", minTimeISPC, width, height);
printf("[rt ispc, 1 core]:\t\t[%.3f] million cycles for %d x %d image\n",
minTimeISPC, width, height);
writeImage(id, image, width, height, "rt-ispc.ppm");
writeImage(id, image, width, height, "rt-ispc-1core.ppm");
memset(id, 0, width*height*sizeof(int));
memset(image, 0, width*height*sizeof(float));
//
// Run 3 iterations with ispc + 1 core, record the minimum time
//
double minTimeISPCtasks = 1e30;
for (int i = 0; i < 3; ++i) {
reset_and_start_timer();
raytrace_ispc_tasks(width, height, raster2camera, camera2world,
image, id, nodes, triangles);
double dt = get_elapsed_mcycles();
minTimeISPCtasks = std::min(dt, minTimeISPCtasks);
}
printf("[rt ispc + tasks]:\t\t[%.3f] million cycles for %d x %d image\n",
minTimeISPCtasks, width, height);
writeImage(id, image, width, height, "rt-ispc-tasks.ppm");
memset(id, 0, width*height*sizeof(int));
memset(image, 0, width*height*sizeof(float));
//
// And 3 iterations with the serial implementation, reporting the
@@ -254,7 +280,8 @@ int main(int argc, char *argv[]) {
}
printf("[rt serial]:\t\t\t[%.3f] million cycles for %d x %d image\n",
minTimeSerial, width, height);
printf("\t\t\t\t(%.2fx speedup from ISPC)\n", minTimeSerial / minTimeISPC);
printf("\t\t\t\t(%.2fx speedup from ISPC, %.2f from ISPC + tasks)\n",
minTimeSerial / minTimeISPC, minTimeSerial / minTimeISPCtasks);
writeImage(id, image, width, height, "rt-serial.ppm");

59
examples/rt/rt.ispc
View File

@@ -226,20 +226,21 @@ bool BVHIntersect(const LinearBVHNode nodes[], const Triangle tris[],
}
export void raytrace(uniform int width, uniform int height,
const uniform float raster2camera[4][4],
const uniform float camera2world[4][4],
uniform float image[], uniform int id[],
const LinearBVHNode nodes[],
const Triangle triangles[]) {
static void raytrace_tile(uniform int x0, uniform int x1,
uniform int y0, uniform int y1, uniform int width,
const uniform float raster2camera[4][4],
const uniform float camera2world[4][4],
uniform float image[], uniform int id[],
const LinearBVHNode nodes[],
const Triangle triangles[]) {
static const uniform float udx[16] = { 0, 1, 0, 1, 2, 3, 2, 3,
0, 1, 0, 1, 2, 3, 2, 3 };
static const uniform float udy[16] = { 0, 0, 1, 1, 0, 0, 1, 1,
2, 2, 3, 3, 2, 2, 3, 3 };
// The outer loops are always over blocks of 4x4 pixels
for (uniform int y = 0; y < height; y += 4) {
for (uniform int x = 0; x < width; x += 4) {
for (uniform int y = y0; y < y1; y += 4) {
for (uniform int x = x0; x < x1; x += 4) {
// Now we have a block of 4x4=16 pixels to process; it will
// take 16/programCount iterations of this loop to process
// them.
@@ -261,3 +262,45 @@ export void raytrace(uniform int width, uniform int height,
}
}
}
export void raytrace_ispc(uniform int width, uniform int height,
const uniform float raster2camera[4][4],
const uniform float camera2world[4][4],
uniform float image[], uniform int id[],
const LinearBVHNode nodes[],
const Triangle triangles[]) {
raytrace_tile(0, width, 0, height, width, raster2camera, camera2world, image,
id, nodes, triangles);
}
task void raytrace_tile_task(uniform int x0, uniform int x1,
uniform int y0, uniform int y1, uniform int width,
const uniform float raster2camera[4][4],
const uniform float camera2world[4][4],
uniform float image[], uniform int id[],
const LinearBVHNode nodes[],
const Triangle triangles[]) {
raytrace_tile(x0, x1, y0, y1, width, raster2camera, camera2world, image,
id, nodes, triangles);
}
export void raytrace_ispc_tasks(uniform int width, uniform int height,
const uniform float raster2camera[4][4],
const uniform float camera2world[4][4],
uniform float image[], uniform int id[],
const LinearBVHNode nodes[],
const Triangle triangles[]) {
uniform int dx = 16, dy = 16;
for (uniform int y = 0; y < height; y += dy) {
uniform int y1 = min(y + dy, height);
for (uniform int x = 0; x < width; x += dx) {
uniform int x1 = min(x + dx, width);
launch < raytrace_tile_task(x, x1, y, y1, width, raster2camera,
camera2world, image, id, nodes,
triangles) >;
}
}
}

3
examples/rt/rt.vcxproj
View File

@@ -164,8 +164,9 @@ ispc -O2 %(Filename).ispc -o %(Filename).obj -h %(Filename)_ispc.h
<ItemGroup>
<ClCompile Include="rt.cpp" />
<ClCompile Include="rt_serial.cpp" />
<ClCompile Include="tasks_concrt.cpp" />
</ItemGroup>
<Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
<ImportGroup Label="ExtensionTargets">
</ImportGroup>
</Project>
</Project>

141
examples/rt/tasks_concrt.cpp Normal file
View File

@@ -0,0 +1,141 @@
/*
Copyright (c) 2010-2011, Intel Corporation
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of Intel Corporation nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* Simple task system implementation for ispc based on Microsoft's
Concurrency Runtime. */
#include <windows.h>
#include <concrt.h>
using namespace Concurrency;
#include <stdint.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
// ispc expects these functions to have C linkage / not be mangled
extern "C" {
void ISPCLaunch(void *f, void *data);
void ISPCSync();
void *ISPCMalloc(int64_t size, int32_t alignment);
void ISPCFree(void *ptr);
}
typedef void (*TaskFuncType)(void *, int, int);
struct TaskInfo {
TaskFuncType ispcFunc;
void *ispcData;
};
// This is a simple implementation that just aborts if more than MAX_TASKS
// are launched. It could easily be extended to be more general...
#define MAX_TASKS 32768
static int taskOffset;
static TaskInfo taskInfo[MAX_TASKS];
static event *events[MAX_TASKS];
static CRITICAL_SECTION criticalSection;
static bool initialized = false;
void
TasksInit() {
InitializeCriticalSection(&criticalSection);
for (int i = 0; i < MAX_TASKS; ++i)
events[i] = new event;
initialized = true;
}
void __cdecl
lRunTask(LPVOID param) {
TaskInfo *ti = (TaskInfo *)param;
// Actually run the task.
// FIXME: like the tasks_gcd.cpp implementation, this is passing bogus
// values for the threadIndex and threadCount builtins, which in turn
// will cause bugs in code that uses those. FWIW this example doesn't
// use them...
int threadIndex = 0;
int threadCount = 1;
ti->ispcFunc(ti->ispcData, threadIndex, threadCount);
// Signal the event that this task is done
int taskNum = ti - &taskInfo[0];
events[taskNum]->set();
}
void
ISPCLaunch(void *func, void *data) {
if (!initialized) {
fprintf(stderr, "You must call TasksInit() before launching tasks.\n");
exit(1);
}
// Get a TaskInfo struct for this task
EnterCriticalSection(&criticalSection);
TaskInfo *ti = &taskInfo[taskOffset++];
assert(taskOffset < MAX_TASKS);
LeaveCriticalSection(&criticalSection);
// And pass it on to the Concurrency Runtime...
ti->ispcFunc = (TaskFuncType)func;
ti->ispcData = data;
CurrentScheduler::ScheduleTask(lRunTask, ti);
}
void ISPCSync() {
if (!initialized) {
fprintf(stderr, "You must call TasksInit() before launching tasks.\n");
exit(1);
}
event::wait_for_multiple(&events[0], taskOffset, true,
COOPERATIVE_TIMEOUT_INFINITE);
for (int i = 0; i < taskOffset; ++i)
events[i]->reset();
taskOffset = 0;
}
void *ISPCMalloc(int64_t size, int32_t alignment) {
return _aligned_malloc(size, alignment);
}
void ISPCFree(void *ptr) {
_aligned_free(ptr);
}

103
examples/rt/tasks_gcd.cpp Normal file
View File

@@ -0,0 +1,103 @@
/*
Copyright (c) 2010-2011, Intel Corporation
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of Intel Corporation nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* A simple task system for ispc programs based on Apple's Grand Central
Dispatch. */
#include <dispatch/dispatch.h>
#include <stdio.h>
#include <stdlib.h>
static bool initialized = false;
static dispatch_queue_t gcdQueue;
static dispatch_group_t gcdGroup;
// ispc expects these functions to have C linkage / not be mangled
extern "C" {
void ISPCLaunch(void *f, void *data);
void ISPCSync();
}
struct TaskInfo {
void *func;
void *data;
};
void
TasksInit() {
gcdQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
gcdGroup = dispatch_group_create();
initialized = true;
}
static void
lRunTask(void *ti) {
typedef void (*TaskFuncType)(void *, int, int);
TaskInfo *taskInfo = (TaskInfo *)ti;
TaskFuncType func = (TaskFuncType)(taskInfo->func);
// FIXME: these are bogus values; may cause bugs in code that depends
// on them having unique values in different threads.
int threadIndex = 0;
int threadCount = 1;
// Actually run the task
func(taskInfo->data, threadIndex, threadCount);
// FIXME: taskInfo leaks...
}
void ISPCLaunch(void *func, void *data) {
if (!initialized) {
fprintf(stderr, "You must call TasksInit() before launching tasks.\n");
exit(1);
}
TaskInfo *ti = new TaskInfo;
ti->func = func;
ti->data = data;
dispatch_group_async_f(gcdGroup, gcdQueue, ti, lRunTask);
}
void ISPCSync() {
if (!initialized) {
fprintf(stderr, "You must call TasksInit() before launching tasks.\n");
exit(1);
}
// Wait for all of the tasks in the group to complete before returning
dispatch_group_wait(gcdGroup, DISPATCH_TIME_FOREVER);
}

295
examples/rt/tasks_pthreads.cpp Normal file
View File

@@ -0,0 +1,295 @@
/*
Copyright (c) 2010-2011, Intel Corporation
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of Intel Corporation nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <pthread.h>
#include <semaphore.h>
#include <string.h>
#include <unistd.h>
#include <assert.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <sys/sysctl.h>
#include <stdint.h>
#include <stdlib.h>
#include <errno.h>
#include <vector>
// ispc expects these functions to have C linkage / not be mangled
extern "C" {
void ISPCLaunch(void *f, void *data);
void ISPCSync();
}
static int nThreads;
static pthread_t *threads;
static pthread_mutex_t taskQueueMutex;
static std::vector<std::pair<void *, void *> > taskQueue;
static sem_t *workerSemaphore;
static uint32_t numUnfinishedTasks;
static pthread_mutex_t tasksRunningConditionMutex;
static pthread_cond_t tasksRunningCondition;
static void *lTaskEntry(void *arg);
/** Figure out how many CPU cores there are in the system
*/
static int
lNumCPUCores() {
#if defined(__linux__)
return sysconf(_SC_NPROCESSORS_ONLN);
#else
// Mac
int mib[2];
mib[0] = CTL_HW;
size_t length = 2;
if (sysctlnametomib("hw.logicalcpu", mib, &length) == -1) {
fprintf(stderr, "sysctlnametomib() filed. Guessing 2 cores.");
return 2;
}
assert(length == 2);
int nCores = 0;
size_t size = sizeof(nCores);
if (sysctl(mib, 2, &nCores, &size, NULL, 0) == -1) {
fprintf(stderr, "sysctl() to find number of cores present failed. Guessing 2.");
return 2;
}
return nCores;
#endif
}
void
TasksInit() {
nThreads = lNumCPUCores();
threads = new pthread_t[nThreads];
int err;
if ((err = pthread_mutex_init(&taskQueueMutex, NULL)) != 0) {
fprintf(stderr, "Error creating mutex: %s\n", strerror(err));
exit(1);
}
char name[32];
sprintf(name, "ispc_task.%d", (int)getpid());
workerSemaphore = sem_open(name, O_CREAT, S_IRUSR|S_IWUSR, 0);
if (!workerSemaphore) {
fprintf(stderr, "Error creating semaphore: %s\n", strerror(err));
exit(1);
}
if ((err = pthread_cond_init(&tasksRunningCondition, NULL)) != 0) {
fprintf(stderr, "Error creating condition variable: %s\n", strerror(err));
exit(1);
}
if ((err = pthread_mutex_init(&tasksRunningConditionMutex, NULL)) != 0) {
fprintf(stderr, "Error creating mutex: %s\n", strerror(err));
exit(1);
}
for (int i = 0; i < nThreads; ++i) {
err = pthread_create(&threads[i], NULL, &lTaskEntry, reinterpret_cast<void *>(i));
if (err != 0) {
fprintf(stderr, "Error creating pthread %d: %s\n", i, strerror(err));
exit(1);
}
}
}
void
ISPCLaunch(void *f, void *d) {
if (threads == NULL) {
fprintf(stderr, "You must call TasksInit() before launching tasks.\n");
exit(1);
}
//
// Acquire mutex, add task
//
int err;
if ((err = pthread_mutex_lock(&taskQueueMutex)) != 0) {
fprintf(stderr, "Error from pthread_mutex_lock: %s\n", strerror(err));
exit(1);
}
taskQueue.push_back(std::make_pair(f, d));
if ((err = pthread_mutex_unlock(&taskQueueMutex)) != 0) {
fprintf(stderr, "Error from pthread_mutex_unlock: %s\n", strerror(err));
exit(1);
}
//
// Update count of number of tasks left to run
//
if ((err = pthread_mutex_lock(&tasksRunningConditionMutex)) != 0) {
fprintf(stderr, "Error from pthread_mutex_lock: %s\n", strerror(err));
exit(1);
}
++numUnfinishedTasks;
if ((err = pthread_mutex_unlock(&tasksRunningConditionMutex)) != 0) {
fprintf(stderr, "Error from pthread_mutex_lock: %s\n", strerror(err));
exit(1);
}
//
// Post to the worker semaphore to wake up worker threads that are
// sleeping waiting for tasks to show up
//
if ((err = sem_post(workerSemaphore)) != 0) {
fprintf(stderr, "Error from sem_post: %s\n", strerror(err));
exit(1);
}
}
static void *
lTaskEntry(void *arg) {
int threadIndex = int(reinterpret_cast<int64_t>(arg));
int threadCount = nThreads;
while (true) {
int err;
if ((err = sem_wait(workerSemaphore)) != 0) {
fprintf(stderr, "Error from sem_wait: %s\n", strerror(err));
exit(1);
}
std::pair<void *, void *> myTask;
//
// Acquire mutex, get task
//
if ((err = pthread_mutex_lock(&taskQueueMutex)) != 0) {
fprintf(stderr, "Error from pthread_mutex_lock: %s\n", strerror(err));
exit(1);
}
if (taskQueue.size() == 0) {
//
// Task queue is empty, go back and wait on the semaphore
//
if ((err = pthread_mutex_unlock(&taskQueueMutex)) != 0) {
fprintf(stderr, "Error from pthread_mutex_unlock: %s\n", strerror(err));
exit(1);
}
continue;
}
myTask = taskQueue.back();
taskQueue.pop_back();
if ((err = pthread_mutex_unlock(&taskQueueMutex)) != 0) {
fprintf(stderr, "Error from pthread_mutex_unlock: %s\n", strerror(err));
exit(1);
}
//
// Do work for _myTask_
//
typedef void (*TaskFunType)(void *, int, int);
TaskFunType func = (TaskFunType)myTask.first;
func(myTask.second, threadIndex, threadCount);
//
// Decrement the number of unfinished tasks counter
//
if ((err = pthread_mutex_lock(&tasksRunningConditionMutex)) != 0) {
fprintf(stderr, "Error from pthread_mutex_lock: %s\n", strerror(err));
exit(1);
}
int unfinished = --numUnfinishedTasks;
if (unfinished == 0) {
//
// Signal the "no more tasks are running" condition if all of
// them are done.
//
int err;
if ((err = pthread_cond_signal(&tasksRunningCondition)) != 0) {
fprintf(stderr, "Error from pthread_cond_signal: %s\n", strerror(err));
exit(1);
}
}
if ((err = pthread_mutex_unlock(&tasksRunningConditionMutex)) != 0) {
fprintf(stderr, "Error from pthread_mutex_lock: %s\n", strerror(err));
exit(1);
}
}
pthread_exit(NULL);
return 0;
}
void ISPCSync() {
if (threads == NULL) {
fprintf(stderr, "You must call TasksInit() before launching tasks.\n");
exit(1);
}
int err;
if ((err = pthread_mutex_lock(&tasksRunningConditionMutex)) != 0) {
fprintf(stderr, "Error from pthread_mutex_lock: %s\n", strerror(err));
exit(1);
}
// As long as there are tasks running, wait on the condition variable;
// doing so causes this thread to go to sleep until someone signals on
// the tasksRunningCondition condition variable.
while (numUnfinishedTasks > 0) {
if ((err = pthread_cond_wait(&tasksRunningCondition,
&tasksRunningConditionMutex)) != 0) {
fprintf(stderr, "Error from pthread_cond_wait: %s\n", strerror(err));
exit(1);
}
}
// We acquire ownership of the condition variable mutex when the above
// pthread_cond_wait returns.
// FIXME: is there a lurking issue here if numUnfinishedTasks gets back
// to zero by the time we get to ISPCSync() and thence we're trying to
// unlock a mutex we don't have a lock on?
if ((err = pthread_mutex_unlock(&tasksRunningConditionMutex)) != 0) {
fprintf(stderr, "Error from pthread_mutex_lock: %s\n", strerror(err));
exit(1);
}
}