1/*
2 * Copyright (c) 2011, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26#include <stdio.h>
27#include <stdint.h>
28#include <stdarg.h>
29#include <unistd.h>
30#include <errno.h>
31#include <string.h>
32#include <sys/resource.h>
33#include <sys/types.h>
34#include <dirent.h>
35#include <stdlib.h>
36#include <dlfcn.h>
37#include <pthread.h>
38#include <inttypes.h>
39#include "com_sun_management_internal_OperatingSystemImpl.h"
40
41struct ticks {
42 uint64_t used;
43 uint64_t usedKernel;
44 uint64_t total;
45};
46
47typedef struct ticks ticks;
48
49typedef enum {
50 CPU_LOAD_VM_ONLY,
51 CPU_LOAD_GLOBAL,
52} CpuLoadTarget;
53
54static struct perfbuf {
55 int nProcs;
56 ticks jvmTicks;
57 ticks cpuTicks;
58 ticks *cpus;
59} counters;
60
61#define DEC_64 "%"SCNd64
62
63static void next_line(FILE *f) {
64 while (fgetc(f) != '\n');
65}
66
67/**
68 * Return the total number of ticks since the system was booted.
69 * If the usedTicks parameter is not NULL, it will be filled with
70 * the number of ticks spent on actual processes (user, system or
71 * nice processes) since system boot. Note that this is the total number
72 * of "executed" ticks on _all_ CPU:s, that is on a n-way system it is
73 * n times the number of ticks that has passed in clock time.
74 *
75 * Returns a negative value if the reading of the ticks failed.
76 */
77static int get_totalticks(int which, ticks *pticks) {
78 FILE *fh;
79 uint64_t userTicks, niceTicks, systemTicks, idleTicks;
80 uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0;
81 int n;
82
83 if((fh = fopen("/proc/stat", "r")) == NULL) {
84 return -1;
85 }
86
87 n = fscanf(fh, "cpu " DEC_64 " " DEC_64 " " DEC_64 " " DEC_64 " " DEC_64 " "
88 DEC_64 " " DEC_64,
89 &userTicks, &niceTicks, &systemTicks, &idleTicks,
90 &iowTicks, &irqTicks, &sirqTicks);
91
92 // Move to next line
93 next_line(fh);
94
95 //find the line for requested cpu faster to just iterate linefeeds?
96 if (which != -1) {
97 int i;
98 for (i = 0; i < which; i++) {
99 if (fscanf(fh, "cpu%*d " DEC_64 " " DEC_64 " " DEC_64 " " DEC_64 " "
100 DEC_64 " " DEC_64 " " DEC_64,
101 &userTicks, &niceTicks, &systemTicks, &idleTicks,
102 &iowTicks, &irqTicks, &sirqTicks) < 4) {
103 fclose(fh);
104 return -2;
105 }
106 next_line(fh);
107 }
108 n = fscanf(fh, "cpu%*d " DEC_64 " " DEC_64 " " DEC_64 " " DEC_64 " "
109 DEC_64 " " DEC_64 " " DEC_64 "\n",
110 &userTicks, &niceTicks, &systemTicks, &idleTicks,
111 &iowTicks, &irqTicks, &sirqTicks);
112 }
113
114 fclose(fh);
115 if (n < 4) {
116 return -2;
117 }
118
119 pticks->used = userTicks + niceTicks;
120 pticks->usedKernel = systemTicks + irqTicks + sirqTicks;
121 pticks->total = userTicks + niceTicks + systemTicks + idleTicks +
122 iowTicks + irqTicks + sirqTicks;
123
124 return 0;
125}
126
127static int vread_statdata(const char *procfile, const char *fmt, va_list args) {
128 FILE *f;
129 int n;
130 char buf[2048];
131
132 if ((f = fopen(procfile, "r")) == NULL) {
133 return -1;
134 }
135
136 if ((n = fread(buf, 1, sizeof(buf), f)) != -1) {
137 char *tmp;
138
139 buf[n-1] = '\0';
140 /** skip through pid and exec name. the exec name _could be wacky_ (renamed) and
141 * make scanf go mupp.
142 */
143 if ((tmp = strrchr(buf, ')')) != NULL) {
144 // skip the ')' and the following space but check that the buffer is long enough
145 tmp += 2;
146 if (tmp < buf + n) {
147 n = vsscanf(tmp, fmt, args);
148 }
149 }
150 }
151
152 fclose(f);
153
154 return n;
155}
156
157static int read_statdata(const char *procfile, const char *fmt, ...) {
158 int n;
159 va_list args;
160
161 va_start(args, fmt);
162 n = vread_statdata(procfile, fmt, args);
163 va_end(args);
164 return n;
165}
166
167/** read user and system ticks from a named procfile, assumed to be in 'stat' format then. */
168static int read_ticks(const char *procfile, uint64_t *userTicks, uint64_t *systemTicks) {
169 return read_statdata(procfile, "%*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u "DEC_64" "DEC_64,
170 userTicks, systemTicks
171 );
172}
173
174/**
175 * Return the number of ticks spent in any of the processes belonging
176 * to the JVM on any CPU.
177 */
178static int get_jvmticks(ticks *pticks) {
179 uint64_t userTicks;
180 uint64_t systemTicks;
181
182 if (read_ticks("/proc/self/stat", &userTicks, &systemTicks) < 0) {
183 return -1;
184 }
185
186 // get the total
187 if (get_totalticks(-1, pticks) < 0) {
188 return -1;
189 }
190
191 pticks->used = userTicks;
192 pticks->usedKernel = systemTicks;
193
194 return 0;
195}
196
197/**
198 * This method must be called first, before any data can be gathererd.
199 */
200int perfInit() {
201 static int initialized=1;
202
203 if (!initialized) {
204 int i;
205
206 int n = sysconf(_SC_NPROCESSORS_ONLN);
207 if (n <= 0) {
208 n = 1;
209 }
210
211 counters.cpus = calloc(n,sizeof(ticks));
212 if (counters.cpus != NULL) {
213 // For the CPU load
214 get_totalticks(-1, &counters.cpuTicks);
215
216 for (i = 0; i < n; i++) {
217 get_totalticks(i, &counters.cpus[i]);
218 }
219 // For JVM load
220 get_jvmticks(&counters.jvmTicks);
221 initialized = 1;
222 }
223 }
224
225 return initialized ? 0 : -1;
226}
227
228#define MAX(a,b) (a>b?a:b)
229#define MIN(a,b) (a<b?a:b)
230
231static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
232
233/**
234 * Return the load of the CPU as a double. 1.0 means the CPU process uses all
235 * available time for user or system processes, 0.0 means the CPU uses all time
236 * being idle.
237 *
238 * Returns a negative value if there is a problem in determining the CPU load.
239 */
240
241static double get_cpuload_internal(int which, double *pkernelLoad, CpuLoadTarget target) {
242 uint64_t udiff, kdiff, tdiff;
243 ticks *pticks, tmp;
244 double user_load = -1.0;
245 int failed = 0;
246
247 *pkernelLoad = 0.0;
248
249 pthread_mutex_lock(&lock);
250
251 if(perfInit() == 0) {
252
253 if (target == CPU_LOAD_VM_ONLY) {
254 pticks = &counters.jvmTicks;
255 } else if (which == -1) {
256 pticks = &counters.cpuTicks;
257 } else {
258 pticks = &counters.cpus[which];
259 }
260
261 tmp = *pticks;
262
263 if (target == CPU_LOAD_VM_ONLY) {
264 if (get_jvmticks(pticks) != 0) {
265 failed = 1;
266 }
267 } else if (get_totalticks(which, pticks) < 0) {
268 failed = 1;
269 }
270
271 if(!failed) {
272 // seems like we sometimes end up with less kernel ticks when
273 // reading /proc/self/stat a second time, timing issue between cpus?
274 if (pticks->usedKernel < tmp.usedKernel) {
275 kdiff = 0;
276 } else {
277 kdiff = pticks->usedKernel - tmp.usedKernel;
278 }
279 tdiff = pticks->total - tmp.total;
280 udiff = pticks->used - tmp.used;
281
282 if (tdiff == 0) {
283 user_load = 0;
284 } else {
285 if (tdiff < (udiff + kdiff)) {
286 tdiff = udiff + kdiff;
287 }
288 *pkernelLoad = (kdiff / (double)tdiff);
289 // BUG9044876, normalize return values to sane values
290 *pkernelLoad = MAX(*pkernelLoad, 0.0);
291 *pkernelLoad = MIN(*pkernelLoad, 1.0);
292
293 user_load = (udiff / (double)tdiff);
294 user_load = MAX(user_load, 0.0);
295 user_load = MIN(user_load, 1.0);
296 }
297 }
298 }
299 pthread_mutex_unlock(&lock);
300 return user_load;
301}
302
303double get_cpu_load(int which) {
304 double u, s;
305 u = get_cpuload_internal(which, &s, CPU_LOAD_GLOBAL);
306 if (u < 0) {
307 return -1.0;
308 }
309 // Cap total systemload to 1.0
310 return MIN((u + s), 1.0);
311}
312
313double get_process_load() {
314 double u, s;
315 u = get_cpuload_internal(-1, &s, CPU_LOAD_VM_ONLY);
316 if (u < 0) {
317 return -1.0;
318 }
319 return u + s;
320}
321
322JNIEXPORT jdouble JNICALL
323Java_com_sun_management_internal_OperatingSystemImpl_getSystemCpuLoad0
324(JNIEnv *env, jobject dummy)
325{
326 if(perfInit() == 0) {
327 return get_cpu_load(-1);
328 } else {
329 return -1.0;
330 }
331}
332
333JNIEXPORT jdouble JNICALL
334Java_com_sun_management_internal_OperatingSystemImpl_getProcessCpuLoad0
335(JNIEnv *env, jobject dummy)
336{
337 if(perfInit() == 0) {
338 return get_process_load();
339 } else {
340 return -1.0;
341 }
342}
343