linux_dsm_epyc7002/arch/x86/include/asm/vgtod.h
Andy Lutomirski 91ec87d57f x86-64: Simplify and optimize vdso clock_gettime monotonic variants
We used to store the wall-to-monotonic offset and the realtime base.
It's faster to precompute the monotonic base.

This is about a 3% speedup on Sandy Bridge for CLOCK_MONOTONIC.
It's much more impressive for CLOCK_MONOTONIC_COARSE.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-03-23 16:49:33 -07:00

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C

#ifndef _ASM_X86_VGTOD_H
#define _ASM_X86_VGTOD_H
#include <asm/vsyscall.h>
#include <linux/clocksource.h>
struct vsyscall_gtod_data {
seqcount_t seq;
struct { /* extract of a clocksource struct */
int vclock_mode;
cycle_t cycle_last;
cycle_t mask;
u32 mult;
u32 shift;
} clock;
/* open coded 'struct timespec' */
time_t wall_time_sec;
u32 wall_time_nsec;
u32 monotonic_time_nsec;
time_t monotonic_time_sec;
struct timezone sys_tz;
struct timespec wall_time_coarse;
struct timespec monotonic_time_coarse;
};
extern struct vsyscall_gtod_data vsyscall_gtod_data;
#endif /* _ASM_X86_VGTOD_H */