forked from mirrors/linux
d0b9d6dcaa
Uses various kernel types that don't build standalone. Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Peter Zijlstra <peterz@infradead.org>
52 lines
1.5 KiB
C
52 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/*
|
|
* sched_clock.h: support for extending counters to full 64-bit ns counter
|
|
*/
|
|
#ifndef LINUX_SCHED_CLOCK
|
|
#define LINUX_SCHED_CLOCK
|
|
|
|
#include <linux/types.h>
|
|
|
|
#ifdef CONFIG_GENERIC_SCHED_CLOCK
|
|
/**
|
|
* struct clock_read_data - data required to read from sched_clock()
|
|
*
|
|
* @epoch_ns: sched_clock() value at last update
|
|
* @epoch_cyc: Clock cycle value at last update.
|
|
* @sched_clock_mask: Bitmask for two's complement subtraction of non 64bit
|
|
* clocks.
|
|
* @read_sched_clock: Current clock source (or dummy source when suspended).
|
|
* @mult: Multiplier for scaled math conversion.
|
|
* @shift: Shift value for scaled math conversion.
|
|
*
|
|
* Care must be taken when updating this structure; it is read by
|
|
* some very hot code paths. It occupies <=40 bytes and, when combined
|
|
* with the seqcount used to synchronize access, comfortably fits into
|
|
* a 64 byte cache line.
|
|
*/
|
|
struct clock_read_data {
|
|
u64 epoch_ns;
|
|
u64 epoch_cyc;
|
|
u64 sched_clock_mask;
|
|
u64 (*read_sched_clock)(void);
|
|
u32 mult;
|
|
u32 shift;
|
|
};
|
|
|
|
extern struct clock_read_data *sched_clock_read_begin(unsigned int *seq);
|
|
extern int sched_clock_read_retry(unsigned int seq);
|
|
|
|
extern void generic_sched_clock_init(void);
|
|
|
|
extern void sched_clock_register(u64 (*read)(void), int bits,
|
|
unsigned long rate);
|
|
#else
|
|
static inline void generic_sched_clock_init(void) { }
|
|
|
|
static inline void sched_clock_register(u64 (*read)(void), int bits,
|
|
unsigned long rate)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
#endif
|