forked from Minki/linux
698eff6355
People reported that commit:5680d8094f("sched/clock: Provide better clock continuity") broke "perf test tsc". That commit added another offset to the reported clock value; so take that into account when computing the provided offset values. Reported-by: Adrian Hunter <adrian.hunter@intel.com> Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org> Tested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes:5680d8094f("sched/clock: Provide better clock continuity") Signed-off-by: Ingo Molnar <mingo@kernel.org>
40 lines
1.0 KiB
C
40 lines
1.0 KiB
C
#ifndef _ASM_X86_TIMER_H
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#define _ASM_X86_TIMER_H
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#include <linux/pm.h>
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#include <linux/percpu.h>
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#include <linux/interrupt.h>
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#include <linux/math64.h>
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#define TICK_SIZE (tick_nsec / 1000)
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unsigned long long native_sched_clock(void);
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extern int recalibrate_cpu_khz(void);
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extern int no_timer_check;
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extern bool using_native_sched_clock(void);
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/*
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* We use the full linear equation: f(x) = a + b*x, in order to allow
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* a continuous function in the face of dynamic freq changes.
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*
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* Continuity means that when our frequency changes our slope (b); we want to
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* ensure that: f(t) == f'(t), which gives: a + b*t == a' + b'*t.
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*
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* Without an offset (a) the above would not be possible.
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*
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* See the comment near cycles_2_ns() for details on how we compute (b).
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*/
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struct cyc2ns_data {
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u32 cyc2ns_mul;
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u32 cyc2ns_shift;
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u64 cyc2ns_offset;
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u32 __count;
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/* u32 hole */
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}; /* 24 bytes -- do not grow */
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extern struct cyc2ns_data *cyc2ns_read_begin(void);
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extern void cyc2ns_read_end(struct cyc2ns_data *);
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#endif /* _ASM_X86_TIMER_H */
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