Re: [PATCH v2 2/2] powerpc/pseries: new lparcfg key/value pair: partition_affinity_score

[Tyrel Datwyler <tyreld@linux.ibm.com>]

On 7/27/20 11:46 AM, Scott Cheloha wrote:
> The H_GetPerformanceCounterInfo (GPCI) PHYP hypercall has a subcall,
> Affinity_Domain_Info_By_Partition, which returns, among other things,
> a "partition affinity score" for a given LPAR.  This score, a value on
> [0-100], represents the processor-memory affinity for the LPAR in
> question.  A score of 0 indicates the worst possible affinity while a
> score of 100 indicates perfect affinity.  The score can be used to
> reason about performance.
> 
> This patch adds the score for the local LPAR to the lparcfg procfile
> under a new 'partition_affinity_score' key.
> 
> Signed-off-by: Scott Cheloha <cheloha@linux.ibm.com>

I was hoping Michael would chime in the first time around on this patch series
about adding another key/value pair to lparcfg. So, barring a NACK from mpe:

Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>

> ---
>  arch/powerpc/platforms/pseries/lparcfg.c | 35 ++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c
> index b8d28ab88178..e278390ab28d 100644
> --- a/arch/powerpc/platforms/pseries/lparcfg.c
> +++ b/arch/powerpc/platforms/pseries/lparcfg.c
> @@ -136,6 +136,39 @@ static unsigned int h_get_ppp(struct hvcall_ppp_data *ppp_data)
>  	return rc;
>  }
>  
> +static void show_gpci_data(struct seq_file *m)
> +{
> +	struct hv_gpci_request_buffer *buf;
> +	unsigned int affinity_score;
> +	long ret;
> +
> +	buf = kmalloc(sizeof(*buf), GFP_KERNEL);
> +	if (buf == NULL)
> +		return;
> +
> +	/*
> +	 * Show the local LPAR's affinity score.
> +	 *
> +	 * 0xB1 selects the Affinity_Domain_Info_By_Partition subcall.
> +	 * The score is at byte 0xB in the output buffer.
> +	 */
> +	memset(&buf->params, 0, sizeof(buf->params));
> +	buf->params.counter_request = cpu_to_be32(0xB1);
> +	buf->params.starting_index = cpu_to_be32(-1);	/* local LPAR */
> +	buf->params.counter_info_version_in = 0x5;	/* v5+ for score */
> +	ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO, virt_to_phys(buf),
> +				 sizeof(*buf));
> +	if (ret != H_SUCCESS) {
> +		pr_debug("hcall failed: H_GET_PERF_COUNTER_INFO: %ld, %x\n",
> +			 ret, be32_to_cpu(buf->params.detail_rc));
> +		goto out;
> +	}
> +	affinity_score = buf->bytes[0xB];
> +	seq_printf(m, "partition_affinity_score=%u\n", affinity_score);
> +out:
> +	kfree(buf);
> +}
> +
>  static unsigned h_pic(unsigned long *pool_idle_time,
>  		      unsigned long *num_procs)
>  {
> @@ -487,6 +520,8 @@ static int pseries_lparcfg_data(struct seq_file *m, void *v)
>  			   partition_active_processors * 100);
>  	}
>  
> +	show_gpci_data(m);
> +
>  	seq_printf(m, "partition_active_processors=%d\n",
>  		   partition_active_processors);
>  
>