[POWERPC] Update wait_state_cycles in the VPA
The hypervisor can look at the value in the wait_state_cycles field of the VPA for an estimate of how busy dedicated processors are. Currently, as the kernel never touches this field, we appear to be 100% busy. This records the duration the kernel is in powersave and passes that to the HV to provide a reasonable indication of utilisation. Signed-off-by: Tony Breeds <tony@bakeyournoodle.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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@ -393,6 +393,7 @@ static void pseries_dedicated_idle_sleep(void)
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{
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unsigned int cpu = smp_processor_id();
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unsigned long start_snooze;
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unsigned long in_purr, out_purr;
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/*
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* Indicate to the HV that we are idle. Now would be
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@ -400,6 +401,7 @@ static void pseries_dedicated_idle_sleep(void)
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*/
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get_lppaca()->idle = 1;
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get_lppaca()->donate_dedicated_cpu = 1;
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in_purr = mfspr(SPRN_PURR);
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/*
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* We come in with interrupts disabled, and need_resched()
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@ -432,6 +434,8 @@ static void pseries_dedicated_idle_sleep(void)
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out:
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HMT_medium();
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out_purr = mfspr(SPRN_PURR);
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get_lppaca()->wait_state_cycles += out_purr - in_purr;
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get_lppaca()->donate_dedicated_cpu = 0;
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get_lppaca()->idle = 0;
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}
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