linux-kernel - Re: [PATCH] pseries/lparcfg: Add resource group monitoring

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Message-ID: <da3a0717-fe3a-49db-bebd-f231a7fdedb7@linux.ibm.com>
Date: Fri, 1 Aug 2025 19:27:22 +0530
From: Shrikanth Hegde <sshegde@...ux.ibm.com>
To: Srikar Dronamraju <srikar@...ux.ibm.com>
Cc: Thomas Gleixner <tglx@...utronix.de>,
        Thomas Weißschuh <thomas.weissschuh@...utronix.de>,
        Tyrel Datwyler <tyreld@...ux.ibm.com>, linux-kernel@...r.kernel.org,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        Madhavan Srinivasan <maddy@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Nicholas Piggin <npiggin@...il.com>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Naveen N Rao <naveen@...nel.org>
Subject: Re: [PATCH] pseries/lparcfg: Add resource group monitoring


On 7/16/25 16:15, Srikar Dronamraju wrote:
> Systems can now be partitioned into resource groups. By default all
> systems will be part of default resource group. Once a resource group is
> created, and resources allocated to the resource group, those resources
> will be removed from the default resource group. If a LPAR moved to a
> resource group, then it can only use resources in the resource group.
> 
> So maximum processors that can be allocated to a LPAR can be equal or
> smaller than the resources in the resource group.
> 
> lparcfg can now exposes the resource group id to which this LPAR belongs
> to. It also exposes the number of processors in the current resource
> group. The default resource group id happens to be 0. These would be
> documented in the upcoming PAPR update.

Could you please add a link to patch on power utils on how it is being consumed?

> 
> Example of an LPAR in a default resource group
> root@...p11-lp3 $ grep resource_group /proc/powerpc/lparcfg
> resource_group_number=0
> resource_group_active_processors=50
> root@...p11-lp3 $
> 
> Example of an LPAR in a non-default resource group
> root@...p11-lp5 $ grep resource_group /proc/powerpc/lparcfg
> resource_group_number=1
> resource_group_active_processors=30
> root@...p11-lp5 $
> 
> Cc: Madhavan Srinivasan <maddy@...ux.ibm.com>
> Cc: Michael Ellerman <mpe@...erman.id.au>
> Cc: Nicholas Piggin <npiggin@...il.com>
> Cc: Christophe Leroy <christophe.leroy@...roup.eu>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: "Thomas Weißschuh" <thomas.weissschuh@...utronix.de>
> Cc: Tyrel Datwyler <tyreld@...ux.ibm.com>
> Cc: linuxppc-dev@...ts.ozlabs.org
> Cc: linux-kernel@...r.kernel.org
> Signed-off-by: Srikar Dronamraju <srikar@...ux.ibm.com>
> ---
>   arch/powerpc/platforms/pseries/lparcfg.c | 17 ++++++++++++++---
>   1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c
> index cc22924f159f..6554537984fb 100644
> --- a/arch/powerpc/platforms/pseries/lparcfg.c
> +++ b/arch/powerpc/platforms/pseries/lparcfg.c

Does MODULE_VERS need to increased?

> @@ -78,6 +78,8 @@ struct hvcall_ppp_data {
>   	u8	capped;
>   	u8	weight;
>   	u8	unallocated_weight;
> +	u8      resource_group_index;
> +	u16     active_procs_in_resource_group;
>   	u16	active_procs_in_pool;
>   	u16	active_system_procs;
>   	u16	phys_platform_procs;
> @@ -86,7 +88,7 @@ struct hvcall_ppp_data {
>   };
>   
>   /*
> - * H_GET_PPP hcall returns info in 4 parms.
> + * H_GET_PPP hcall returns info in 5 parms.
>    *  entitled_capacity,unallocated_capacity,
>    *  aggregation, resource_capability).
>    *
> @@ -94,11 +96,11 @@ struct hvcall_ppp_data {
>    *  R5 = Unallocated Processor Capacity Percentage.
>    *  R6 (AABBCCDDEEFFGGHH).
>    *      XXXX - reserved (0)
> - *          XXXX - reserved (0)
> + *          XXXX - Active Cores in Resource Group
>    *              XXXX - Group Number
>    *                  XXXX - Pool Number.
>    *  R7 (IIJJKKLLMMNNOOPP).
> - *      XX - reserved. (0)
> + *      XX - Resource group Number
>    *        XX - bit 0-6 reserved (0).   bit 7 is Capped indicator.
>    *          XX - variable processor Capacity Weight
>    *            XX - Unallocated Variable Processor Capacity Weight.
> @@ -120,9 +122,11 @@ static unsigned int h_get_ppp(struct hvcall_ppp_data *ppp_data)
>   	ppp_data->entitlement = retbuf[0];
>   	ppp_data->unallocated_entitlement = retbuf[1];
>   
> +	ppp_data->active_procs_in_resource_group = (retbuf[2] >> 4 * 8) & 0xffff;
>   	ppp_data->group_num = (retbuf[2] >> 2 * 8) & 0xffff;
>   	ppp_data->pool_num = retbuf[2] & 0xffff;
>   
> +	ppp_data->resource_group_index = (retbuf[3] >> 7 *  8) & 0xff;
>   	ppp_data->capped = (retbuf[3] >> 6 * 8) & 0x01;
>   	ppp_data->weight = (retbuf[3] >> 5 * 8) & 0xff;
>   	ppp_data->unallocated_weight = (retbuf[3] >> 4 * 8) & 0xff;
> @@ -236,6 +240,13 @@ static void parse_ppp_data(struct seq_file *m)
>   	seq_printf(m, "unallocated_capacity=%lld\n",
>   		   ppp_data.unallocated_entitlement);
>   
> +	if (ppp_data.active_procs_in_resource_group)  {

ppp_data.active_procs_in_resource_group can ever be zero?

If the entry is absent in lparcfg, then lparstat will print it as 0 (which happens to be
default RG, while default RG may have processors)

> +		seq_printf(m, "resource_group_number=%d\n",
> +				ppp_data.resource_group_index);
> +		seq_printf(m, "resource_group_active_processors=%d\n",
> +				ppp_data.active_procs_in_resource_group);
> +	}
> +
>   	/* The last bits of information returned from h_get_ppp are only
>   	 * valid if the ibm,partition-performance-parameters-level
>   	 * property is >= 1.