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Commit f927da17 authored by Isaku Yamahata's avatar Isaku Yamahata Committed by Tony Luck
Browse files

ia64/pv_ops/pv_time_ops: add sched_clock hook. 



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: default avatarIsaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent 496203b1

arch/ia64/include/asm/paravirt.h

+7 −0
Original line number Diff line number Diff line
@@ -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

arch/ia64/include/asm/timex.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */

arch/ia64/kernel/head.S

+8 −2
Original line number Diff line number Diff line
@@ -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)

arch/ia64/kernel/paravirt.c

+1 −0
Original line number Diff line number Diff line
@@ -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,

};

arch/ia64/kernel/time.c

+9 −0
Original line number Diff line number Diff line
@@ -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)