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ia64/pv_ops/pv_time_ops: add sched_clock hook.

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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>
This commit is contained in:
Isaku Yamahata 2009-03-04 21:05:40 +09:00 committed by Tony Luck
parent 496203b15b
commit f927da1786
5 changed files with 26 additions and 2 deletions
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7
arch/ia64/include/asm/paravirt.h
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@ -225,6 +225,8 @@ struct pv_time_ops {
int (*do_steal_accounting)(unsigned long *new_itm);
void (*clocksource_resume)(void);
unsigned long long (*sched_clock)(void);
};
extern struct pv_time_ops pv_time_ops;
@ -242,6 +244,11 @@ paravirt_do_steal_accounting(unsigned long *new_itm)
return pv_time_ops.do_steal_accounting(new_itm);
}
static inline unsigned long long paravirt_sched_clock(void)
{
return pv_time_ops.sched_clock();
}
#endif /* !__ASSEMBLY__ */
#else

1
arch/ia64/include/asm/timex.h
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@ -40,5 +40,6 @@ get_cycles (void)
}
extern void ia64_cpu_local_tick (void);
extern unsigned long long ia64_native_sched_clock (void);
#endif /* _ASM_IA64_TIMEX_H */

10
arch/ia64/kernel/head.S
View File

@ -1050,7 +1050,7 @@ END(ia64_delay_loop)
* except that the multiplication and the shift are done with 128-bit
* intermediate precision so that we can produce a full 64-bit result.
*/
GLOBAL_ENTRY(sched_clock)
GLOBAL_ENTRY(ia64_native_sched_clock)
addl r8=THIS_CPU(cpu_info) + IA64_CPUINFO_NSEC_PER_CYC_OFFSET,r0
mov.m r9=ar.itc // fetch cycle-counter (35 cyc)
;;
@ -1066,7 +1066,13 @@ GLOBAL_ENTRY(sched_clock)
;;
shrp r8=r9,r8,IA64_NSEC_PER_CYC_SHIFT
br.ret.sptk.many rp
END(sched_clock)
END(ia64_native_sched_clock)
#ifndef CONFIG_PARAVIRT
//unsigned long long
//sched_clock(void) __attribute__((alias("ia64_native_sched_clock")));
.global sched_clock
sched_clock = ia64_native_sched_clock
#endif
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
GLOBAL_ENTRY(cycle_to_cputime)

1
arch/ia64/kernel/paravirt.c
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@ -366,4 +366,5 @@ ia64_native_do_steal_accounting(unsigned long *new_itm)
struct pv_time_ops pv_time_ops = {
.do_steal_accounting = ia64_native_do_steal_accounting,
.sched_clock = ia64_native_sched_clock,
};

9
arch/ia64/kernel/time.c
View File

@ -49,6 +49,15 @@ EXPORT_SYMBOL(last_cli_ip);
#endif
#ifdef CONFIG_PARAVIRT
/* We need to define a real function for sched_clock, to override the
weak default version */
unsigned long long sched_clock(void)
{
return paravirt_sched_clock();
}
#endif
#ifdef CONFIG_PARAVIRT
static void
paravirt_clocksource_resume(void)