Subject: Re: [PATCH 2/4] powerpc/pseries: Add wait interval counters to VPA

From: Fabiano Rosas <[email-masked]>
Date: Fri, 27 May 2022 17:25:26 -0300

Nicholas Piggin <[email-masked]> writes:

> The hypervisor exposes accumulated partition scheduling interval times
> in the VPA (lppaca). These can be used to implement a simple stolen time
> in the guest without complex and costly dtl scanning.
>
> Signed-off-by: Nicholas Piggin <[email-masked]>
> ---
>  arch/powerpc/include/asm/lppaca.h | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/lppaca.h b/arch/powerpc/include/asm/lppaca.h
> index c390ec377bae..34d44cb17c87 100644
> --- a/arch/powerpc/include/asm/lppaca.h
> +++ b/arch/powerpc/include/asm/lppaca.h
> @@ -104,14 +104,18 @@ struct lppaca {
>  	volatile __be32 dispersion_count; /* dispatch changed physical cpu */
>  	volatile __be64 cmo_faults;	/* CMO page fault count */
>  	volatile __be64 cmo_fault_time;	/* CMO page fault time */
> -	u8	reserved10[104];
> +	u8	reserved10[64];		/* [S]PURR expropriated/donated */
> +	volatile __be64 enqueue_dispatch_tb; /* Total TB enqueue->dispatch */
> +	volatile __be64 ready_enqueue_tb; /* Total TB ready->enqueue */
> +	volatile __be64 wait_ready_tb;	/* Total TB wait->ready */

This last one is unused but I assume you are adding anyway it because it
could be later added to lparcfg. So:

Reviewed-by: Fabiano Rosas <[email-masked]>