linux-kernel - Re: [PATCH 2/3] powerpc/sysfs: Show idle_purr and idle

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Message-ID: <20200203044735.GB13468@in.ibm.com>
Date:   Mon, 3 Feb 2020 10:17:35 +0530
From:   Gautham R Shenoy <ego@...ux.vnet.ibm.com>
To:     Nathan Lynch <nathanl@...ux.ibm.com>
Cc:     "Gautham R. Shenoy" <ego@...ux.vnet.ibm.com>,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        Michael Ellerman <mpe@...erman.id.au>,
        Vaidyanathan Srinivasan <svaidy@...ux.vnet.ibm.com>,
        Kamalesh Babulal <kamalesh@...ux.vnet.ibm.com>,
        "Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>,
        Tyrel Datwyler <tyreld@...ux.ibm.com>
Subject: Re: [PATCH 2/3] powerpc/sysfs: Show idle_purr and idle_spurr for
 every CPU

Hello Nathan,


On Wed, Dec 04, 2019 at 04:24:31PM -0600, Nathan Lynch wrote:
> "Gautham R. Shenoy" <ego@...ux.vnet.ibm.com> writes:
> > @@ -1067,6 +1097,8 @@ static int __init topology_init(void)
> >  			register_cpu(c, cpu);
> >  
> >  			device_create_file(&c->dev, &dev_attr_physical_id);
> > +			if (firmware_has_feature(FW_FEATURE_SPLPAR))
> > +				create_idle_purr_spurr_sysfs_entry(&c->dev);
> 
> Architecturally speaking PURR/SPURR aren't strongly linked to the PAPR
> SPLPAR option, are they? I'm not sure it's right for these attributes to
> be absent if the platform does not support shared processor mode.

Doesn't FW_FEATURE_SPLPAR refer to all Pseries guests ? It is perhaps
incorrectly named, but from the other uses in the kernel, it seems to
indicate that we are running as a guest instead of on a bare-metal
system.

--
Thanks and Regards
gautham.