Annotation of /trunk/src/lib/parallel-target/cpu.c

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1 :	jhr	1232	/*! \file cpu.c
2 :			*
3 :			* \author John Reppy
4 :			*/
5 :
6 :			/*
7 :			* COPYRIGHT (c) 2011 The Diderot Project (http://diderot-language.cs.uchicago.edu)
8 :			* All rights reserved.
9 :			*/
10 :
11 :			#include "Diderot/diderot.h"
12 :			#if defined (__APPLE__)
13 :			# include <sys/sysctl.h>
14 :			#endif
15 :			#ifdef HAVE_LIBNUMA
16 :			# include <numa.h>
17 :			#endif
18 :			#include <errno.h>
19 :
20 :			/*! \brief determine the number of CPUs */
21 :			bool GetNumCPUs (CPUInfo_t *info)
22 :			{
23 :			#if defined(HAVE__PROC_CPUINFO)
24 :			/* Get information from /proc/cpuinfo. The interesting
25 :			* fields are:
26 :			*
27 :			* processor : <id> # logical processor id
28 :			* physical id : <id> # node id
29 :			* core id : <id> # core id (per node)
30 :			* cpu cores : <n> # number of cores per node
31 :			*/
32 :			FILE *cpuinfo = fopen("/proc/cpuinfo", "r");
33 :			char buf[1024];
34 :			if (cpuinfo != NULL) {
35 :			int maxProcId = 0, maxNodeId = 0, maxCoreId = 0, nCores = 0;
36 :			while (fgets(buf, sizeof(buf), cpuinfo) != 0) {
37 :			int tmp;
38 :			if (sscanf(buf, "processor : %d", &tmp) == 1) {
39 :			maxProcId = (tmp > maxProcId) ? tmp : maxProcId;
40 :			}
41 :			else if (sscanf(buf, "physical id : %d", &tmp) == 1) {
42 :			maxNodeId = (tmp > maxNodeId) ? tmp : maxNodeId;
43 :			}
44 :			else if (sscanf(buf, "core id : %d", &tmp) == 1) {
45 :			maxCoreId = (tmp > maxCoreId) ? tmp : maxCoreId;
46 :			}
47 :			else if (sscanf(buf, "cpu cores : %d", &tmp) == 1) {
48 :			nCores = (tmp > nCores) ? tmp : nCores;
49 :			}
50 :			}
51 :			fclose (cpuinfo);
52 :
53 :			#ifdef HAVE_LIBNUMA
54 :			info->numHWThreads = info->numHWCores = maxProcId + 1;
55 :			info->numHWNodes = numa_max_node()+1;
56 :			info->numThdsPerCore = 1;
57 :			info->numCoresPerNode = info->numHWThreads / info->numHWNodes;
58 :			#else
59 :			info->numHWNodes = maxNodeId + 1;
60 :			info->numHWCores = info->numHWNodes * nCores;
61 :			info->numHWThreads = maxProcId + 1;
62 :			info->numCoresPerNode = nCores;
63 :			info->numThdsPerCore = info->numHWThreads / info->numHWCores;
64 :			#endif
65 :
66 :			return true;
67 :			}
68 :			else {
69 :			fprintf(stderr, "unable to determine the number of processors\n");
70 :			return false;
71 :			}
72 :			#elif defined(__APPLE__)
73 :			size_t len = sizeof(int);
74 :
75 :			/* the number of nodes */
76 :			if (sysctlbyname("hw.packages", &(info->numHWNodes), &len, 0, 0) < 0) {
77 :			if (errno == ENOENT) {
78 :			// "hw.packages" is not known
79 :			info->numHWNodes = 1;
80 :			}
81 :			else {
82 :			fprintf(stderr, "unable to determine the number of nodes\n");
83 :			return false;
84 :			}
85 :			}
86 :
87 :			/* the number of cores */
88 :			if (sysctlbyname("hw.physicalcpu", &(info->numHWCores), &len, 0, 0) < 0) {
89 :			fprintf(stderr, "unable to determine the number of physical CPUs\n");
90 :			return false;
91 :			}
92 :
93 :			/* the number of hardware threads */
94 :			if (sysctlbyname("hw.logicalcpu", &(info->numHWThreads), &len, 0, 0) < 0) {
95 :			if (errno == ENOENT) {
96 :			// "hw.packages" is not known
97 :			info->numHWThreads = info->numHWCores;
98 :			}
99 :			else {
100 :			fprintf(stderr, "unable to determine the number of logical CPUs\n");
101 :			return false;
102 :			}
103 :			}
104 :
105 :			info->numCoresPerNode = info->numHWCores / info->numHWNodes;
106 :			info->numThdsPerCore = info->numHWThreads / info->numHWCores;
107 :
108 :			return true;
109 :			#else
110 :			return false;
111 :			#endif
112 :
113 :			} /* end of GetNumCPUs */

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