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d2912cb1 | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
112f38a4 RK |
2 | /* |
3 | * sched_clock.h: support for extending counters to full 64-bit ns counter | |
112f38a4 | 4 | */ |
38ff87f7 SB |
5 | #ifndef LINUX_SCHED_CLOCK |
6 | #define LINUX_SCHED_CLOCK | |
112f38a4 | 7 | |
d0b9d6dc IM |
8 | #include <linux/types.h> |
9 | ||
38ff87f7 | 10 | #ifdef CONFIG_GENERIC_SCHED_CLOCK |
1b86abc1 PZ |
11 | /** |
12 | * struct clock_read_data - data required to read from sched_clock() | |
13 | * | |
14 | * @epoch_ns: sched_clock() value at last update | |
15 | * @epoch_cyc: Clock cycle value at last update. | |
16 | * @sched_clock_mask: Bitmask for two's complement subtraction of non 64bit | |
17 | * clocks. | |
18 | * @read_sched_clock: Current clock source (or dummy source when suspended). | |
cc00c198 | 19 | * @mult: Multiplier for scaled math conversion. |
1b86abc1 PZ |
20 | * @shift: Shift value for scaled math conversion. |
21 | * | |
22 | * Care must be taken when updating this structure; it is read by | |
23 | * some very hot code paths. It occupies <=40 bytes and, when combined | |
24 | * with the seqcount used to synchronize access, comfortably fits into | |
25 | * a 64 byte cache line. | |
26 | */ | |
27 | struct clock_read_data { | |
28 | u64 epoch_ns; | |
29 | u64 epoch_cyc; | |
30 | u64 sched_clock_mask; | |
31 | u64 (*read_sched_clock)(void); | |
32 | u32 mult; | |
33 | u32 shift; | |
34 | }; | |
35 | ||
36 | extern struct clock_read_data *sched_clock_read_begin(unsigned int *seq); | |
37 | extern int sched_clock_read_retry(unsigned int seq); | |
38 | ||
5d2a4e91 | 39 | extern void generic_sched_clock_init(void); |
38ff87f7 | 40 | |
e7e3ff1b SB |
41 | extern void sched_clock_register(u64 (*read)(void), int bits, |
42 | unsigned long rate); | |
364eba4b | 43 | #else |
5d2a4e91 | 44 | static inline void generic_sched_clock_init(void) { } |
364eba4b DL |
45 | |
46 | static inline void sched_clock_register(u64 (*read)(void), int bits, | |
47 | unsigned long rate) | |
48 | { | |
364eba4b DL |
49 | } |
50 | #endif | |
211baa70 | 51 | |
112f38a4 | 52 | #endif |