f927da1786
add sched_clock() hook to paravirtualize sched_clock(). ia64 sched_clock() is based on ar.itc which isn't stable on virtualized environment because vcpu may move around on pcpus. So it needs paravirtualization. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Tony Luck <tony.luck@intel.com>
46 lines
1.4 KiB
C
46 lines
1.4 KiB
C
#ifndef _ASM_IA64_TIMEX_H
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#define _ASM_IA64_TIMEX_H
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/*
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* Copyright (C) 1998-2001, 2003 Hewlett-Packard Co
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* David Mosberger-Tang <davidm@hpl.hp.com>
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*/
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/*
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* 2001/01/18 davidm Removed CLOCK_TICK_RATE. It makes no sense on IA-64.
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* Also removed cacheflush_time as it's entirely unused.
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*/
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#include <asm/intrinsics.h>
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#include <asm/processor.h>
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typedef unsigned long cycles_t;
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extern void (*ia64_udelay)(unsigned long usecs);
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/*
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* For performance reasons, we don't want to define CLOCK_TICK_TRATE as
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* local_cpu_data->itc_rate. Fortunately, we don't have to, either: according to George
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* Anzinger, 1/CLOCK_TICK_RATE is taken as the resolution of the timer clock. The time
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* calculation assumes that you will use enough of these so that your tick size <= 1/HZ.
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* If the calculation shows that your CLOCK_TICK_RATE can not supply exactly 1/HZ ticks,
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* the actual value is calculated and used to update the wall clock each jiffie. Setting
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* the CLOCK_TICK_RATE to x*HZ insures that the calculation will find no errors. Hence we
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* pick a multiple of HZ which gives us a (totally virtual) CLOCK_TICK_RATE of about
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* 100MHz.
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*/
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#define CLOCK_TICK_RATE (HZ * 100000UL)
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static inline cycles_t
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get_cycles (void)
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{
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cycles_t ret;
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ret = ia64_getreg(_IA64_REG_AR_ITC);
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return ret;
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}
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extern void ia64_cpu_local_tick (void);
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extern unsigned long long ia64_native_sched_clock (void);
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#endif /* _ASM_IA64_TIMEX_H */
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