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source: vbox/trunk/src/VBox/Runtime/r3/linux/mp-linux.cpp@ 82968

Last change on this file since 82968 was 82968, checked in by vboxsync, 4 years ago

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1/* $Id: mp-linux.cpp 82968 2020-02-04 10:35:17Z vboxsync $ */
2/** @file
3 * IPRT - Multiprocessor, Linux.
4 */
5
6/*
7 * Copyright (C) 2006-2020 Oracle Corporation
8 *
9 * This file is part of VirtualBox Open Source Edition (OSE), as
10 * available from http://www.virtualbox.org. This file is free software;
11 * you can redistribute it and/or modify it under the terms of the GNU
12 * General Public License (GPL) as published by the Free Software
13 * Foundation, in version 2 as it comes in the "COPYING" file of the
14 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16 *
17 * The contents of this file may alternatively be used under the terms
18 * of the Common Development and Distribution License Version 1.0
19 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20 * VirtualBox OSE distribution, in which case the provisions of the
21 * CDDL are applicable instead of those of the GPL.
22 *
23 * You may elect to license modified versions of this file under the
24 * terms and conditions of either the GPL or the CDDL or both.
25 */
26
27
28/*********************************************************************************************************************************
29* Header Files *
30*********************************************************************************************************************************/
31#define LOG_GROUP RTLOGGROUP_SYSTEM
32#include <stdio.h>
33#include <errno.h>
34
35#include <iprt/mp.h>
36#include "internal/iprt.h"
37
38#include <iprt/alloca.h>
39#include <iprt/cpuset.h>
40#include <iprt/assert.h>
41#include <iprt/string.h>
42#include <iprt/linux/sysfs.h>
43
44
45/**
46 * Internal worker that determines the max possible CPU count.
47 *
48 * @returns Max cpus.
49 */
50static RTCPUID rtMpLinuxMaxCpus(void)
51{
52#if 0 /* this doesn't do the right thing :-/ */
53 int cMax = sysconf(_SC_NPROCESSORS_CONF);
54 Assert(cMax >= 1);
55 return cMax;
56#else
57 static uint32_t s_cMax = 0;
58 if (!s_cMax)
59 {
60 int cMax = 1;
61 for (unsigned iCpu = 0; iCpu < RTCPUSET_MAX_CPUS; iCpu++)
62 if (RTLinuxSysFsExists("devices/system/cpu/cpu%d", iCpu))
63 cMax = iCpu + 1;
64 ASMAtomicUoWriteU32((uint32_t volatile *)&s_cMax, cMax);
65 return cMax;
66 }
67 return s_cMax;
68#endif
69}
70
71/**
72 * Internal worker that picks the processor speed in MHz from /proc/cpuinfo.
73 *
74 * @returns CPU frequency.
75 */
76static uint32_t rtMpLinuxGetFrequency(RTCPUID idCpu)
77{
78 FILE *pFile = fopen("/proc/cpuinfo", "r");
79 if (!pFile)
80 return 0;
81
82 char sz[256];
83 RTCPUID idCpuFound = NIL_RTCPUID;
84 uint32_t Frequency = 0;
85 while (fgets(sz, sizeof(sz), pFile))
86 {
87 char *psz;
88 if ( !strncmp(sz, RT_STR_TUPLE("processor"))
89 && (sz[10] == ' ' || sz[10] == '\t' || sz[10] == ':')
90 && (psz = strchr(sz, ':')))
91 {
92 psz += 2;
93 int64_t iCpu;
94 int rc = RTStrToInt64Ex(psz, NULL, 0, &iCpu);
95 if (RT_SUCCESS(rc))
96 idCpuFound = iCpu;
97 }
98 else if ( idCpu == idCpuFound
99 && !strncmp(sz, RT_STR_TUPLE("cpu MHz"))
100 && (sz[10] == ' ' || sz[10] == '\t' || sz[10] == ':')
101 && (psz = strchr(sz, ':')))
102 {
103 psz += 2;
104 int64_t v;
105 int rc = RTStrToInt64Ex(psz, &psz, 0, &v);
106 if (RT_SUCCESS(rc))
107 {
108 Frequency = v;
109 break;
110 }
111 }
112 }
113 fclose(pFile);
114 return Frequency;
115}
116
117
118/** @todo RTmpCpuId(). */
119
120RTDECL(int) RTMpCpuIdToSetIndex(RTCPUID idCpu)
121{
122 return idCpu < rtMpLinuxMaxCpus() ? (int)idCpu : -1;
123}
124
125
126RTDECL(RTCPUID) RTMpCpuIdFromSetIndex(int iCpu)
127{
128 return (unsigned)iCpu < rtMpLinuxMaxCpus() ? iCpu : NIL_RTCPUID;
129}
130
131
132RTDECL(RTCPUID) RTMpGetMaxCpuId(void)
133{
134 return rtMpLinuxMaxCpus() - 1;
135}
136
137
138RTDECL(bool) RTMpIsCpuOnline(RTCPUID idCpu)
139{
140 /** @todo check if there is a simpler interface than this... */
141 int64_t i = 0;
142 int rc = RTLinuxSysFsReadIntFile(0, &i, "devices/system/cpu/cpu%d/online", (int)idCpu);
143 if ( RT_FAILURE(rc)
144 && RTLinuxSysFsExists("devices/system/cpu/cpu%d", (int)idCpu))
145 {
146 /** @todo Assert(!RTLinuxSysFsExists("devices/system/cpu/cpu%d/online",
147 * (int)idCpu));
148 * Unfortunately, the online file wasn't always world readable (centos
149 * 2.6.18-164). */
150 i = 1;
151 rc = VINF_SUCCESS;
152 }
153
154 AssertMsg(i == 0 || i == -1 || i == 1, ("i=%d\n", i));
155 return RT_SUCCESS(rc) && i != 0;
156}
157
158
159RTDECL(bool) RTMpIsCpuPossible(RTCPUID idCpu)
160{
161 /** @todo check this up with hotplugging! */
162 return RTLinuxSysFsExists("devices/system/cpu/cpu%d", (int)idCpu);
163}
164
165
166RTDECL(PRTCPUSET) RTMpGetSet(PRTCPUSET pSet)
167{
168 RTCpuSetEmpty(pSet);
169 RTCPUID cMax = rtMpLinuxMaxCpus();
170 for (RTCPUID idCpu = 0; idCpu < cMax; idCpu++)
171 if (RTMpIsCpuPossible(idCpu))
172 RTCpuSetAdd(pSet, idCpu);
173 return pSet;
174}
175
176
177RTDECL(RTCPUID) RTMpGetCount(void)
178{
179 RTCPUSET Set;
180 RTMpGetSet(&Set);
181 return RTCpuSetCount(&Set);
182}
183
184
185RTDECL(RTCPUID) RTMpGetCoreCount(void)
186{
187 RTCPUID cMax = rtMpLinuxMaxCpus();
188 uint32_t *paidCores = (uint32_t *)alloca(sizeof(paidCores[0]) * (cMax + 1));
189 uint32_t *paidPckgs = (uint32_t *)alloca(sizeof(paidPckgs[0]) * (cMax + 1));
190 uint32_t cCores = 0;
191 for (RTCPUID idCpu = 0; idCpu < cMax; idCpu++)
192 {
193 if (RTMpIsCpuPossible(idCpu))
194 {
195 int64_t idCore = 0;
196 int64_t idPckg = 0;
197
198 int rc = RTLinuxSysFsReadIntFile(0, &idCore, "devices/system/cpu/cpu%d/topology/core_id", (int)idCpu);
199 if (RT_SUCCESS(rc))
200 rc = RTLinuxSysFsReadIntFile(0, &idPckg, "devices/system/cpu/cpu%d/topology/physical_package_id", (int)idCpu);
201
202 if (RT_SUCCESS(rc))
203 {
204 uint32_t i;
205
206 for (i = 0; i < cCores; i++)
207 if ( paidCores[i] == (uint32_t)idCore
208 && paidPckgs[i] == (uint32_t)idPckg)
209 break;
210 if (i >= cCores)
211 {
212 paidCores[cCores] = (uint32_t)idCore;
213 paidPckgs[cCores] = (uint32_t)idPckg;
214 cCores++;
215 }
216 }
217 }
218 }
219 Assert(cCores > 0);
220 return cCores;
221}
222
223
224RTDECL(PRTCPUSET) RTMpGetOnlineSet(PRTCPUSET pSet)
225{
226 RTCpuSetEmpty(pSet);
227 RTCPUID cMax = rtMpLinuxMaxCpus();
228 for (RTCPUID idCpu = 0; idCpu < cMax; idCpu++)
229 if (RTMpIsCpuOnline(idCpu))
230 RTCpuSetAdd(pSet, idCpu);
231 return pSet;
232}
233
234
235RTDECL(RTCPUID) RTMpGetOnlineCount(void)
236{
237 RTCPUSET Set;
238 RTMpGetOnlineSet(&Set);
239 return RTCpuSetCount(&Set);
240}
241
242
243RTDECL(RTCPUID) RTMpGetOnlineCoreCount(void)
244{
245 RTCPUID cMax = rtMpLinuxMaxCpus();
246 uint32_t *paidCores = (uint32_t *)alloca(sizeof(paidCores[0]) * (cMax + 1));
247 uint32_t *paidPckgs = (uint32_t *)alloca(sizeof(paidPckgs[0]) * (cMax + 1));
248 uint32_t cCores = 0;
249 for (RTCPUID idCpu = 0; idCpu < cMax; idCpu++)
250 {
251 if (RTMpIsCpuOnline(idCpu))
252 {
253 int64_t idCore = 0;
254 int64_t idPckg = 0;
255
256 int rc = RTLinuxSysFsReadIntFile(0, &idCore, "devices/system/cpu/cpu%d/topology/core_id", (int)idCpu);
257 if (RT_SUCCESS(rc))
258 rc = RTLinuxSysFsReadIntFile(0, &idPckg, "devices/system/cpu/cpu%d/topology/physical_package_id", (int)idCpu);
259
260 if (RT_SUCCESS(rc))
261 {
262 uint32_t i;
263
264 for (i = 0; i < cCores; i++)
265 if ( paidCores[i] == idCore
266 && paidPckgs[i] == idPckg)
267 break;
268 if (i >= cCores)
269 {
270 paidCores[cCores] = idCore;
271 paidPckgs[cCores] = idPckg;
272 cCores++;
273 }
274 }
275 }
276 }
277 Assert(cCores > 0);
278 return cCores;
279}
280
281
282
283RTDECL(uint32_t) RTMpGetCurFrequency(RTCPUID idCpu)
284{
285 int64_t kHz = 0;
286 int rc = RTLinuxSysFsReadIntFile(0, &kHz, "devices/system/cpu/cpu%d/cpufreq/cpuinfo_cur_freq", (int)idCpu);
287 if (RT_FAILURE(rc))
288 {
289 /*
290 * The file may be just unreadable - in that case use plan B, i.e.
291 * /proc/cpuinfo to get the data we want. The assumption is that if
292 * cpuinfo_cur_freq doesn't exist then the speed won't change, and
293 * thus cur == max. If it does exist then cpuinfo contains the
294 * current frequency.
295 */
296 kHz = rtMpLinuxGetFrequency(idCpu) * 1000;
297 }
298 return (kHz + 999) / 1000;
299}
300
301
302RTDECL(uint32_t) RTMpGetMaxFrequency(RTCPUID idCpu)
303{
304 int64_t kHz = 0;
305 int rc = RTLinuxSysFsReadIntFile(0, &kHz, "devices/system/cpu/cpu%d/cpufreq/cpuinfo_max_freq", (int)idCpu);
306 if (RT_FAILURE(rc))
307 {
308 /*
309 * Check if the file isn't there - if it is there, then /proc/cpuinfo
310 * would provide current frequency information, which is wrong.
311 */
312 if (!RTLinuxSysFsExists("devices/system/cpu/cpu%d/cpufreq/cpuinfo_max_freq", (int)idCpu))
313 kHz = rtMpLinuxGetFrequency(idCpu) * 1000;
314 else
315 kHz = 0;
316 }
317 return (kHz + 999) / 1000;
318}
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