1/* Copyright (C) 2001-2019 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public License as
6 published by the Free Software Foundation; either version 2.1 of the
7 License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If
16 not, see <http://www.gnu.org/licenses/>. */
17
18#include <errno.h>
19#include <stdlib.h>
20#include <time.h>
21#include "pthreadP.h"
22
23
24#if HP_TIMING_AVAIL
25int
26__pthread_clock_gettime (clockid_t clock_id, hp_timing_t freq,
27 struct timespec *tp)
28{
29 hp_timing_t tsc;
30
31 /* Get the current counter. */
32 HP_TIMING_NOW (tsc);
33
34 /* This is the ID of the thread we are looking for. */
35 pid_t tid = ((unsigned int) clock_id) >> CLOCK_IDFIELD_SIZE;
36
37 /* Compute the offset since the start time of the process. */
38 if (tid == 0 || tid == THREAD_GETMEM (THREAD_SELF, tid))
39 /* Our own clock. */
40 tsc -= THREAD_GETMEM (THREAD_SELF, cpuclock_offset);
41 else
42 {
43 /* This is more complicated. We have to locate the thread based
44 on the ID. This means walking the list of existing
45 threads. */
46 struct pthread *thread = __find_thread_by_id (tid);
47 if (thread == NULL)
48 {
49 __set_errno (EINVAL);
50 return -1;
51 }
52
53 /* There is a race here. The thread might terminate and the stack
54 become unusable. But this is the user's problem. */
55 tsc -= thread->cpuclock_offset;
56 }
57
58 /* Compute the seconds. */
59 tp->tv_sec = tsc / freq;
60
61 /* And the nanoseconds. This computation should be stable until
62 we get machines with about 16GHz frequency. */
63 tp->tv_nsec = ((tsc % freq) * 1000000000ull) / freq;
64
65 return 0;
66}
67#endif
68