Project2-Ju Yang

README.md

@@ -1,13 +1,69 @@
 CUDA Stream Compaction
 ======================
 
-**University of Pennsylvania, CIS 565: GPU Programming and Architecture, Project 2**
+###University of Pennsylvania, CIS 565: GPU Programming and Architecture, Project 2
 
-* (TODO) YOUR NAME HERE
-* Tested on: (TODO) Windows 22, i7-2222 @ 2.22GHz 22GB, GTX 222 222MB (Moore 2222 Lab)
+Ju Yang 
 
-### (TODO: Your README)
+### Tested on: Windows 7, i7-4710MQ @ 2.50GHz 8GB, GTX 870M 6870MB (Hasee Notebook K770E-i7)
+![result](doc/1024.png)
 
-Include analysis, etc. (Remember, this is public, so don't put
-anything here that you don't want to share with the world.)
+## TODOs finished: 
+  ### 1. naive.cu 
+
+  __global__ void naive_sum(int n,int* odata, int* idata);
+
+  void scan(int n, int *odata, const int *idata);  
+
+  ### 2. efficient.cu 
+
+  __global__ void prescan(int *g_odata, int *g_idata, int n, int*temp);
+
+  void scan(int n, int *odata, const int *idata);
+
+  int compact(int n, int *odata, const int *idata);
+
 
+  ### 3 thrust.cu 
+
+  void scan(int n, int *odata, const int *idata);
+
+
+  ### 4 cpu.cu 
+
+  void scan(int n, int *odata, const int *idata);
+
+  int compactWithoutScan(int n, int *odata, const int *idata) ;
+
+  int compactWithScan(int n, int *odata, const int *idata);
+
+  ### 5 common.cu 
+
+  __global__ void kernMapToBoolean(int n, int *bools, const int *idata);
+
+  __global__ void kernScatter(int n, int *odata,
+                const int *idata, const int *bools, const int *indices);
+
+ ### Modified the main.cpp a little bit for display. 
+
+## Performance Graph
+
+ ### Scanning
+ ![result](doc/image001.gif)
+ ### Thrust Scanning
+ ![result](doc/data_29123_image001.gif)
+ ### Compact
+ ![result](doc/data_6317_image001.gif)
+
+## Analysis
+ ### Thrust
+ As we can see, the thrust::exclusive_scan is rather time-costing compared with other methods. Even if I used device_vector to store the data, it is still the slowest. 
+ But since I did not free the device_vectors, the non-pow2 as second round's speed is much faster. 
+ I think the reason is, when calling thrust functions, it will apply for some blocks/threads inside the GPU, and will release later on. 
+ Although I tried my best to avoid any read/write from CPU to GPU, the scan function still cost some time to arrange for some place. 
+
+ ### Unfixed Known Bugs
+  #### 1. When using multiple blocks, sometimes the result is not right. I think it is because __syncthreads() doesn't sync blocks?
+  #### 2. Since I used only 1 block, when the SIZE is more than 1024(which is the limit), apperently the result is wrong. 
+  #### 3. CPU performace is much better, and sometimes the calculating time doesn't always raise with the SIZE. 
+           I think this is because the SIZE is still not large enough? 

src/main.cpp

@@ -13,14 +13,17 @@
 #include <stream_compaction/thrust.h>
 #include "testing_helpers.hpp"
 
-const int SIZE = 1 << 8; // feel free to change the size of array
+
+
+const int SIZE = 1 << 10; // feel free to change the size of array
 const int NPOT = SIZE - 3; // Non-Power-Of-Two
 int a[SIZE], b[SIZE], c[SIZE];
 
 int main(int argc, char* argv[]) {
+
     // Scan tests
+	printf("Size= %d, Non-Pow2 Size= %d. \n", SIZE, NPOT);
 
-    printf("\n");
     printf("****************\n");
     printf("** SCAN TESTS **\n");
     printf("****************\n");
@@ -42,7 +45,7 @@ int main(int argc, char* argv[]) {
     printDesc("cpu scan, non-power-of-two");
     StreamCompaction::CPU::scan(NPOT, c, a);
     printElapsedTime(StreamCompaction::CPU::timer().getCpuElapsedTimeForPreviousOperation(), "(std::chrono Measured)");
-    printArray(NPOT, b, true);
+    //printArray(NPOT, b, true);
     printCmpResult(NPOT, b, c);
 
     zeroArray(SIZE, c);
@@ -115,14 +118,14 @@ int main(int argc, char* argv[]) {
     count = StreamCompaction::CPU::compactWithoutScan(NPOT, c, a);
     printElapsedTime(StreamCompaction::CPU::timer().getCpuElapsedTimeForPreviousOperation(), "(std::chrono Measured)");
     expectedNPOT = count;
-    printArray(count, c, true);
+    //printArray(count, c, true);
     printCmpLenResult(count, expectedNPOT, b, c);
 
     zeroArray(SIZE, c);
     printDesc("cpu compact with scan");
     count = StreamCompaction::CPU::compactWithScan(SIZE, c, a);
     printElapsedTime(StreamCompaction::CPU::timer().getCpuElapsedTimeForPreviousOperation(), "(std::chrono Measured)");
-    printArray(count, c, true);
+    //printArray(count, c, true);
     printCmpLenResult(count, expectedCount, b, c);
 
     zeroArray(SIZE, c);

stream_compaction/common.cu

@@ -24,6 +24,15 @@ namespace StreamCompaction {
          */
         __global__ void kernMapToBoolean(int n, int *bools, const int *idata) {
             // TODO
+			int index = threadIdx.x;
+			if (idata[index] == 0)//If this is 0
+			{
+				bools[index] = 0;
+			}
+			else
+			{
+				bools[index] = 1;
+			}
         }
 
         /**
@@ -33,6 +42,13 @@ namespace StreamCompaction {
         __global__ void kernScatter(int n, int *odata,
                 const int *idata, const int *bools, const int *indices) {
             // TODO
+
+			int index = threadIdx.x;
+
+			if (bools[index]!=0)
+			{
+				odata[indices[index]] = idata[index];
+			}
         }
 
     }

stream_compaction/cpu.cu

@@ -1,15 +1,15 @@
 #include <cstdio>
 #include "cpu.h"
 
-#include "common.h"
+#include "common.h"
 
 namespace StreamCompaction {
     namespace CPU {
-        using StreamCompaction::Common::PerformanceTimer;
-        PerformanceTimer& timer()
-        {
-	        static PerformanceTimer timer;
-	        return timer;
+        using StreamCompaction::Common::PerformanceTimer;
+        PerformanceTimer& timer()
+        {
+	        static PerformanceTimer timer;
+	        return timer;
         }
 
         /**
@@ -20,6 +20,14 @@ namespace StreamCompaction {
         void scan(int n, int *odata, const int *idata) {
 	        timer().startCpuTimer();
             // TODO
+			int i;
+			int count=0;
+
+			for (i = 0; i < n; i++)
+			{
+				count += idata[i];
+				odata[i] = count;
+			}
 	        timer().endCpuTimer();
         }
 
@@ -31,8 +39,21 @@ namespace StreamCompaction {
         int compactWithoutScan(int n, int *odata, const int *idata) {
 	        timer().startCpuTimer();
             // TODO
+			int i;
+			int count = 0;
+			for (i = 0; i < n; i++)
+			{
+				if (idata[i] != 0)
+				{
+					odata[i-count] = idata[i];				
+				}
+				else
+				{
+					count++;
+				}
+			}
 	        timer().endCpuTimer();
-            return -1;
+            return n-count;
         }
 
         /**
@@ -43,8 +64,23 @@ namespace StreamCompaction {
         int compactWithScan(int n, int *odata, const int *idata) {
 	        timer().startCpuTimer();
 	        // TODO
+			int i;
+			int count=0;
+
+			for (i = 0; i < n; i++)
+			{
+				if (idata[i] != 0)
+				{
+					odata[i - count] = idata[i];
+				}
+				else
+				{
+					count++;
+				}
+			}
+
 	        timer().endCpuTimer();
-            return -1;
+            return n- count;
         }
     }
 }