Actual source code: ex2.c
petsc-3.4.5 2014-06-29
1: static const char help[] = "STREAM benchmark for pthread implemenentations\n\n";
3: /*-----------------------------------------------------------------------*/
4: /* Program: Stream */
5: /* Revision: $Id: stream.c,v 5.9 2009/04/11 16:35:00 mccalpin Exp mccalpin $ */
6: /* Original code developed by John D. McCalpin */
7: /* Programmers: John D. McCalpin */
8: /* Joe R. Zagar */
9: /* */
10: /* This program measures memory transfer rates in MB/s for simple */
11: /* computational kernels coded in C. */
12: /*-----------------------------------------------------------------------*/
13: /* Copyright 1991-2005: John D. McCalpin */
14: /*-----------------------------------------------------------------------*/
15: /* License: */
16: /* 1. You are free to use this program and/or to redistribute */
17: /* this program. */
18: /* 2. You are free to modify this program for your own use, */
19: /* including commercial use, subject to the publication */
20: /* restrictions in item 3. */
21: /* 3. You are free to publish results obtained from running this */
22: /* program, or from works that you derive from this program, */
23: /* with the following limitations: */
24: /* 3a. In order to be referred to as "STREAM benchmark results", */
25: /* published results must be in conformance to the STREAM */
26: /* Run Rules, (briefly reviewed below) published at */
27: /* http://www.cs.virginia.edu/stream/ref.html */
28: /* and incorporated herein by reference. */
29: /* As the copyright holder, John McCalpin retains the */
30: /* right to determine conformity with the Run Rules. */
31: /* 3b. Results based on modified source code or on runs not in */
32: /* accordance with the STREAM Run Rules must be clearly */
33: /* labelled whenever they are published. Examples of */
34: /* proper labelling include: */
35: /* "tuned STREAM benchmark results" */
36: /* "based on a variant of the STREAM benchmark code" */
37: /* Other comparable, clear and reasonable labelling is */
38: /* acceptable. */
39: /* 3c. Submission of results to the STREAM benchmark web site */
40: /* is encouraged, but not required. */
41: /* 4. Use of this program or creation of derived works based on this */
42: /* program constitutes acceptance of these licensing restrictions. */
43: /* 5. Absolutely no warranty is expressed or implied. */
44: /*-----------------------------------------------------------------------*/
45: # include <float.h>
46: # include <sys/time.h>
47: # include <petscsys.h>
48: # include <petscthreadcomm.h>
49: /* INSTRUCTIONS:
50: *
51: * 1) Stream requires a good bit of memory to run. Adjust the
52: * value of 'N' (below) to give a 'timing calibration' of
53: * at least 20 clock-ticks. This will provide rate estimates
54: * that should be good to about 5% precision.
55: */
57: #if !defined(N)
58: # define N 2000000
59: #endif
60: #if !defined(NTIMES)
61: # define NTIMES 50
62: #endif
63: #if !defined(OFFSET)
64: # define OFFSET 0
65: #endif
67: /*
68: * 3) Compile the code with full optimization. Many compilers
69: * generate unreasonably bad code before the optimizer tightens
70: * things up. If the results are unreasonably good, on the
71: * other hand, the optimizer might be too smart for me!
72: *
73: * Try compiling with:
74: * cc -O stream_omp.c -o stream_omp
75: *
76: * This is known to work on Cray, SGI, IBM, and Sun machines.
77: *
78: *
79: * 4) Mail the results to mccalpin@cs.virginia.edu
80: * Be sure to include:
81: * a) computer hardware model number and software revision
82: * b) the compiler flags
83: * c) all of the output from the test case.
84: * Thanks!
85: *
86: */
88: # define HLINE "-------------------------------------------------------------\n"
90: # if !defined(MIN)
91: # define MIN(x,y) ((x)<(y) ? (x) : (y))
92: # endif
93: # if !defined(MAX)
94: # define MAX(x,y) ((x)>(y) ? (x) : (y))
95: # endif
97: #if !defined(STATIC_ALLOC)
98: # define STATIC_ALLOC 1
99: #endif
101: #if STATIC_ALLOC
102: static double a[N+OFFSET],
103: b[N+OFFSET],
104: c[N+OFFSET];
105: #endif
107: static double avgtime[4] = {0}, maxtime[4] = {0},
108: mintime[4] = {FLT_MAX,FLT_MAX,FLT_MAX,FLT_MAX};
110: static const char *label[4] = {"Copy: ", "Scale: ","Add: ", "Triad: "};
112: static double bytes[4] = {
113: 2 * sizeof(double) * N,
114: 2 * sizeof(double) * N,
115: 3 * sizeof(double) * N,
116: 3 * sizeof(double) * N
117: };
119: double mysecond();
120: void checkSTREAMresults();
122: #if !defined(WITH_PTHREADS)
123: # define WITH_PTHREADS 1
124: #endif
126: #if !STATIC_ALLOC
127: double *a, *b, *c;
128: #endif
130: #if WITH_PTHREADS
131: PetscInt nworkThreads;
132: PetscInt *trstarts;
134: PetscErrorCode tuned_STREAM_2A_Kernel(PetscInt myrank)
135: {
136: int i;
138: for (i=trstarts[myrank]; i<trstarts[myrank+1]; i++) a[i] = 2.0E0*a[i];
140: return(0);
141: }
143: PetscErrorCode tuned_STREAM_Initialize_Kernel(PetscInt myrank)
144: {
145: int i;
147: for (i=trstarts[myrank]; i<trstarts[myrank+1]; i++) {
148: a[i] = 1.0;
149: b[i] = 2.0;
150: c[i] = 0.0;
151: }
152: return(0);
153: }
155: PetscErrorCode tuned_STREAM_Copy_Kernel(PetscInt myrank)
156: {
157: int j;
159: for (j=trstarts[myrank]; j<trstarts[myrank+1]; j++) c[j] = a[j];
160: return(0);
161: }
163: PetscErrorCode tuned_STREAM_Scale_Kernel(PetscInt myrank,double *scalarp)
164: {
165: double scalar = *scalarp;
166: int j;
168: for (j=trstarts[myrank]; j<trstarts[myrank+1]; j++) b[j] = scalar*c[j];
169: return(0);
170: }
172: PetscErrorCode tuned_STREAM_Add_Kernel(PetscInt myrank)
173: {
174: int j;
176: for (j=trstarts[myrank]; j<trstarts[myrank+1]; j++) c[j] = a[j]+b[j];
178: return(0);
179: }
181: PetscErrorCode tuned_STREAM_Triad_Kernel(PetscInt myrank,double *scalarp)
182: {
183: double scalar = *scalarp;
184: int j;
186: for (j=trstarts[myrank]; j<trstarts[myrank+1]; j++) a[j] = b[j]+scalar*c[j];
188: return(0);
189: }
190: #endif
192: int main(int argc,char *argv[])
193: {
195: int quantum, checktick();
196: int BytesPerWord;
197: int j, k;
198: double scalar=3.0, t, times[4][NTIMES];
200: PetscInitialize(&argc,&argv,0,help);
201: /* --- SETUP --- determine precision and check timing --- */
203: /*printf(HLINE);
204: printf("STREAM version $Revision: 5.9 $\n");
205: printf(HLINE); */
206: BytesPerWord = sizeof(double);
207: printf("This system uses %d bytes per DOUBLE PRECISION word.\n",BytesPerWord);
209: printf(HLINE);
210: #if defined(NO_LONG_LONG)
211: printf("Array size = %d, Offset = %d\n", N, OFFSET);
212: #else
213: printf("Array size = %llu, Offset = %d\n", (unsigned long long) N, OFFSET);
214: #endif
216: printf("Total memory required = %.1f MB.\n",(3.0 * BytesPerWord) * ((double)N / 1048576.0));
217: printf("Each test is run %d times, but only\n", NTIMES);
218: printf("the *best* time for each is used.\n");
220: printf(HLINE);
222: #if !STATIC_ALLOC
223: a = malloc((N+OFFSET)*sizeof(double));
224: b = malloc((N+OFFSET)*sizeof(double));
225: c = malloc((N+OFFSET)*sizeof(double));
226: #endif
228: #if WITH_PTHREADS
229: PetscThreadCommGetNThreads(PETSC_COMM_WORLD,&nworkThreads);
230: PetscMalloc((nworkThreads+1)*sizeof(PetscInt),&trstarts);
231: PetscInt Q,R,nloc;
232: PetscBool S;
233: Q = (N+OFFSET)/nworkThreads;
234: R = (N+OFFSET) - Q*nworkThreads;
235: trstarts[0] = 0;
236: for (j=0; j < nworkThreads; j++) {
237: S = (PetscBool)(j < R);
238: nloc = S ? Q+1 : Q;
239: trstarts[j+1] = trstarts[j]+nloc;
240: }
241: PetscThreadCommRunKernel(PETSC_COMM_WORLD,(PetscThreadKernel)tuned_STREAM_Initialize_Kernel,1,&scalar);
242: PetscThreadCommBarrier(PETSC_COMM_WORLD);
243: # else
244: for (j=0; j<N; j++) {
245: a[j] = 1.0;
246: b[j] = 2.0;
247: c[j] = 0.0;
248: }
249: #endif
251: /*printf(HLINE);*/
253: /* Get initial value for system clock. */
254: if ((quantum = checktick()) >= 1) ;
255: /* printf("Your clock granularity/precision appears to be %d microseconds.\n", quantum); */
256: else quantum = 1;
257: /* printf("Your clock granularity appears to be less than one microsecond.\n"); */
259: t = mysecond();
261: #if WITH_PTHREADS
262: PetscThreadCommRunKernel(PETSC_COMM_WORLD,(PetscThreadKernel)tuned_STREAM_2A_Kernel,0);
263: PetscThreadCommBarrier(PETSC_COMM_WORLD);
264: #else
265: for (j = 0; j < N; j++) a[j] = 2.0E0 * a[j];
266: #endif
267: t = 1.0E6 * (mysecond() - t);
269: /* printf("Each test below will take on the order of %d microseconds.\n", (int)t);
270: printf(" (= %d clock ticks)\n", (int) (t/quantum));
271: printf("Increase the size of the arrays if this shows that\n");
272: printf("you are not getting at least 20 clock ticks per test.\n");
274: printf(HLINE);
275: */
276: /* --- MAIN LOOP --- repeat test cases NTIMES times --- */
278: for (k=0; k<NTIMES; k++) {
279: times[0][k] = mysecond();
280: #if WITH_PTHREADS
281: PetscThreadCommRunKernel(PETSC_COMM_WORLD,(PetscThreadKernel)tuned_STREAM_Copy_Kernel,0);
282: PetscThreadCommBarrier(PETSC_COMM_WORLD);
283: #else
284: for (j=0; j<N; j++) c[j] = a[j];
285: #endif
286: times[0][k] = mysecond() - times[0][k];
288: times[1][k] = mysecond();
289: #if WITH_PTHREADS
290: PetscThreadCommRunKernel(PETSC_COMM_WORLD,(PetscThreadKernel)tuned_STREAM_Scale_Kernel,1,&scalar);
291: PetscThreadCommBarrier(PETSC_COMM_WORLD);
292: #else
293: for (j=0; j<N; j++) b[j] = scalar*c[j];
294: #endif
295: times[1][k] = mysecond() - times[1][k];
297: times[2][k] = mysecond();
298: #if WITH_PTHREADS
299: PetscThreadCommRunKernel(PETSC_COMM_WORLD,(PetscThreadKernel)tuned_STREAM_Add_Kernel,0);
300: PetscThreadCommBarrier(PETSC_COMM_WORLD);
301: #else
302: for (j=0; j<N; j++) c[j] = a[j]+b[j];
303: #endif
304: times[2][k] = mysecond() - times[2][k];
306: times[3][k] = mysecond();
307: #if WITH_PTHREADS
308: PetscThreadCommRunKernel(PETSC_COMM_WORLD,(PetscThreadKernel)tuned_STREAM_Triad_Kernel,1,&scalar);
309: PetscThreadCommBarrier(PETSC_COMM_WORLD);
310: #else
311: for (j=0; j<N; j++) a[j] = b[j]+scalar*c[j];
312: #endif
313: times[3][k] = mysecond() - times[3][k];
314: }
316: /* --- SUMMARY --- */
318: for (k=1; k<NTIMES; k++) /* note -- skip first iteration */
319: for (j=0; j<4; j++) {
320: avgtime[j] = avgtime[j] + times[j][k];
321: mintime[j] = MIN(mintime[j], times[j][k]);
322: maxtime[j] = MAX(maxtime[j], times[j][k]);
323: }
325: printf("Function Rate (MB/s) \n");
326: for (j=0; j<4; j++) {
327: avgtime[j] = avgtime[j]/(double)(NTIMES-1);
329: printf("%s%11.4f \n", label[j], 1.0E-06 * bytes[j]/mintime[j]);
330: }
331: /* printf(HLINE);*/
332: #if WITH_PTHREADS
333: PetscThreadCommBarrier(PETSC_COMM_WORLD);
334: #endif
335: /* --- Check Results --- */
336: checkSTREAMresults();
337: /* printf(HLINE);*/
338: PetscFinalize();
339: return 0;
340: }
342: # define M 20
344: int checktick()
345: {
346: int i, minDelta, Delta;
347: double t1, t2, timesfound[M];
349: /* Collect a sequence of M unique time values from the system. */
351: for (i = 0; i < M; i++) {
352: t1 = mysecond();
353: while (((t2=mysecond()) - t1) < 1.0E-6) ;
354: timesfound[i] = t1 = t2;
355: }
357: /*
358: * Determine the minimum difference between these M values.
359: * This result will be our estimate (in microseconds) for the
360: * clock granularity.
361: */
363: minDelta = 1000000;
364: for (i = 1; i < M; i++) {
365: Delta = (int)(1.0E6 * (timesfound[i]-timesfound[i-1]));
366: minDelta = MIN(minDelta, MAX(Delta,0));
367: }
369: return(minDelta);
370: }
372: /* A gettimeofday routine to give access to the wall
373: clock timer on most UNIX-like systems. */
375: #include <sys/time.h>
377: double mysecond()
378: {
379: struct timeval tp;
380: struct timezone tzp;
381: int i=0;
383: i = gettimeofday(&tp,&tzp);
384: return ((double) tp.tv_sec + (double) tp.tv_usec * 1.e-6);
385: }
387: void checkSTREAMresults()
388: {
389: double aj,bj,cj,scalar;
390: double asum,bsum,csum;
391: double epsilon;
392: int j,k;
394: /* reproduce initialization */
395: aj = 1.0;
396: bj = 2.0;
397: cj = 0.0;
398: /* a[] is modified during timing check */
399: aj = 2.0E0 * aj;
400: /* now execute timing loop */
401: scalar = 3.0;
402: for (k=0; k<NTIMES; k++) {
403: cj = aj;
404: bj = scalar*cj;
405: cj = aj+bj;
406: aj = bj+scalar*cj;
407: }
408: aj = aj * (double) (N);
409: bj = bj * (double) (N);
410: cj = cj * (double) (N);
412: asum = 0.0;
413: bsum = 0.0;
414: csum = 0.0;
415: for (j=0; j<N; j++) {
416: asum += a[j];
417: bsum += b[j];
418: csum += c[j];
419: }
420: #if defined(VERBOSE)
421: printf ("Results Comparison: \n");
422: printf (" Expected : %f %f %f \n",aj,bj,cj);
423: printf (" Observed : %f %f %f \n",asum,bsum,csum);
424: #endif
426: #if !defined(abs)
427: #define abs(a) ((a) >= 0 ? (a) : -(a))
428: #endif
429: epsilon = 1.e-8;
431: if (abs(aj-asum)/asum > epsilon) {
432: printf ("Failed Validation on array a[]\n");
433: printf (" Expected : %f \n",aj);
434: printf (" Observed : %f \n",asum);
435: }
436: if (abs(bj-bsum)/bsum > epsilon) {
437: printf ("Failed Validation on array b[]\n");
438: printf (" Expected : %f \n",bj);
439: printf (" Observed : %f \n",bsum);
440: }
441: if (abs(cj-csum)/csum > epsilon) {
442: printf ("Failed Validation on array c[]\n");
443: printf (" Expected : %f \n",cj);
444: printf (" Observed : %f \n",csum);
445: } /* else printf ("Solution Validates\n"); */
446: }