1 /*-
2  *   BSD LICENSE
3  *
4  *   Copyright(c) 2015 Intel Corporation. All rights reserved.
5  *   All rights reserved.
6  *
7  *   Redistribution and use in source and binary forms, with or without
8  *   modification, are permitted provided that the following conditions
9  *   are met:
10  *
11  *     * Redistributions of source code must retain the above copyright
12  *       notice, this list of conditions and the following disclaimer.
13  *     * Redistributions in binary form must reproduce the above copyright
14  *       notice, this list of conditions and the following disclaimer in
15  *       the documentation and/or other materials provided with the
16  *       distribution.
17  *     * Neither the name of Intel Corporation nor the names of its
18  *       contributors may be used to endorse or promote products derived
19  *       from this software without specific prior written permission.
20  *
21  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 
35 #ifndef LTHREAD_TIMER_H_
36 #define LTHREAD_TIMER_H_
37 
38 #ifdef __cplusplus
39 extern "C" {
40 #endif
41 
42 #include "lthread_int.h"
43 #include "lthread_sched.h"
44 
45 
46 static inline uint64_t
47 _ns_to_clks(uint64_t ns)
48 {
49 	/*
50 	 * clkns needs to be divided by 1E9 to get ns clocks. However,
51 	 * dividing by this first would lose a lot of accuracy.
52 	 * Dividing after a multiply by ns, could cause overflow of
53 	 * uint64_t if ns is about 5 seconds [if we assume a max tsc
54 	 * rate of 4GHz]. Therefore we first divide by 1E4, then
55 	 * multiply and finally divide by 1E5. This allows ns to be
56 	 * values many hours long, without overflow, while still keeping
57 	 * reasonable accuracy.
58 	 */
59 	uint64_t clkns = rte_get_tsc_hz() / 1e4;
60 
61 	clkns *= ns;
62 	clkns /= 1e5;
63 
64 	return clkns;
65 }
66 
67 
68 static inline void
69 _timer_start(struct lthread *lt, uint64_t clks)
70 {
71 	if (clks > 0) {
72 		DIAG_EVENT(lt, LT_DIAG_LTHREAD_TMR_START, &lt->tim, clks);
73 		rte_timer_init(&lt->tim);
74 		rte_timer_reset(&lt->tim,
75 				clks,
76 				SINGLE,
77 				rte_lcore_id(),
78 				_sched_timer_cb,
79 				(void *)lt);
80 	}
81 }
82 
83 
84 static inline void
85 _timer_stop(struct lthread *lt)
86 {
87 	if (lt != NULL) {
88 		DIAG_EVENT(lt, LT_DIAG_LTHREAD_TMR_DELETE, &lt->tim, 0);
89 		rte_timer_stop(&lt->tim);
90 	}
91 }
92 
93 #ifdef __cplusplus
94 }
95 #endif
96 
97 #endif /* LTHREAD_TIMER_H_ */
98