[PATCH] powerpc/pseries: export timebase register sample in lparcfg

[Tyrel Datwyler]

Ping? Any objections to this patch? A fix is already upstream in powerpc-utils
to utilize the timebase value if available.

-Tyrel

On 12/08/2018 03:48 PM, Tyrel Datwyler wrote:
> The Processor Utilzation of Resource Registers (PURR) provide an estimate of
> resources used by a cpu thread. Section 7.6 in Book III of the ISA outlines
> how to calculate the percentage of shared resources for threads using the
> ratio of the PURR delta and Timebase Register delta for a sampled period.
> 
> This calculation is currently done erroneously by the lparstat tool from the
> powerpc-utils package. This patch exports the current timebase value after
> we sample the PURRs and exposes it to userspace accounting tools via
> /proc/ppc64/lparcfg.
> 
> Signed-off-by: Tyrel Datwyler <tyreld at linux.vnet.ibm.com>
> ---
>  arch/powerpc/platforms/pseries/lparcfg.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c
> index 7944873..1ea73ec 100644
> --- a/arch/powerpc/platforms/pseries/lparcfg.c
> +++ b/arch/powerpc/platforms/pseries/lparcfg.c
> @@ -475,6 +475,7 @@ static int pseries_lparcfg_data(struct seq_file *m, void *v)
>  		splpar_dispatch_data(m);
> 
>  		seq_printf(m, "purr=%ld\n", get_purr());
> +        seq_printf(m, "tbr=%ld\n", mftb());
>  	} else {		/* non SPLPAR case */
> 
>  		seq_printf(m, "system_active_processors=%d\n",
>