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[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>
This commit is contained in:
Tony Breeds 2008-03-17 16:23:29 +11:00 committed by Paul Mackerras
parent 71e91a0abb
commit 96366a8d3f
1 changed files with 4 additions and 0 deletions
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4
arch/powerpc/platforms/pseries/setup.c
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@ -393,6 +393,7 @@ static void pseries_dedicated_idle_sleep(void)
{
unsigned int cpu = smp_processor_id();
unsigned long start_snooze;
unsigned long in_purr, out_purr;
/*
* Indicate to the HV that we are idle. Now would be
@ -400,6 +401,7 @@ static void pseries_dedicated_idle_sleep(void)
*/
get_lppaca()->idle = 1;
get_lppaca()->donate_dedicated_cpu = 1;
in_purr = mfspr(SPRN_PURR);
/*
* We come in with interrupts disabled, and need_resched()
@ -432,6 +434,8 @@ static void pseries_dedicated_idle_sleep(void)
out:
HMT_medium();
out_purr = mfspr(SPRN_PURR);
get_lppaca()->wait_state_cycles += out_purr - in_purr;
get_lppaca()->donate_dedicated_cpu = 0;
get_lppaca()->idle = 0;
}