1 | /* Copyright (C) 2001-2017 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 <libc-internal.h> |
22 | #include "pthreadP.h" |
23 | |
24 | |
25 | #if HP_TIMING_AVAIL |
26 | int |
27 | __pthread_clock_gettime (clockid_t clock_id, hp_timing_t freq, |
28 | struct timespec *tp) |
29 | { |
30 | hp_timing_t tsc; |
31 | |
32 | /* Get the current counter. */ |
33 | HP_TIMING_NOW (tsc); |
34 | |
35 | /* This is the ID of the thread we are looking for. */ |
36 | pid_t tid = ((unsigned int) clock_id) >> CLOCK_IDFIELD_SIZE; |
37 | |
38 | /* Compute the offset since the start time of the process. */ |
39 | if (tid == 0 || tid == THREAD_GETMEM (THREAD_SELF, tid)) |
40 | /* Our own clock. */ |
41 | tsc -= THREAD_GETMEM (THREAD_SELF, cpuclock_offset); |
42 | else |
43 | { |
44 | /* This is more complicated. We have to locate the thread based |
45 | on the ID. This means walking the list of existing |
46 | threads. */ |
47 | struct pthread *thread = __find_thread_by_id (tid); |
48 | if (thread == NULL) |
49 | { |
50 | __set_errno (EINVAL); |
51 | return -1; |
52 | } |
53 | |
54 | /* There is a race here. The thread might terminate and the stack |
55 | become unusable. But this is the user's problem. */ |
56 | tsc -= thread->cpuclock_offset; |
57 | } |
58 | |
59 | /* Compute the seconds. */ |
60 | tp->tv_sec = tsc / freq; |
61 | |
62 | /* And the nanoseconds. This computation should be stable until |
63 | we get machines with about 16GHz frequency. */ |
64 | tp->tv_nsec = ((tsc % freq) * 1000000000ull) / freq; |
65 | |
66 | return 0; |
67 | } |
68 | #endif |
69 | |