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Date: Mon, 21 Dec 2015 06:53:20 -0600 (CST)
From: Christoph Lameter <cl@linux.com>
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To: Marcelo Tosatti <mtosatti@redhat.com>
cc: Fenghua Yu <fenghua.yu@intel.com>, "H. Peter Anvin" <hpa@linux.intel.com>,
        Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
        Tony Luck <tony.luck@intel.com>,
        Ravi V Shankar <ravi.v.shankar@intel.com>,
        Peter Zijlstra <peterz@infradead.org>, Tejun Heo <tj@kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
Subject: Re: [PATCH V16 00/11] x86: Intel Cache Allocation Technology
 Support
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On Fri, 18 Dec 2015, Marcelo Tosatti wrote:

> > Could you also support another low level interface where a task (or
> > process) can set the CLOS id itself if it has CAP_SYS_NICE.
>
> Hi Christoph,
>
> Do you have a proposal for an interface?

Syscall set_closid(int closid) for an app. The CLOS id should be
listed in /proc/<pid>/status

And then /proc/clos listing the possible configs with their current
setups.

Or /proc/clos/<closid>/<value>. Then have the ability to modify
those for the root user.

> >  Plus some way
> > for the supervisor to directly control the IA32_L3_MASK_n MSR?
>
> What you mean supervisor? Hypervisor or root user?

Root user.
>
> > Is there a way to see these values for debugging purposes?
>
> Yes, from userspace, wrmsr and rdmsr.

Maybe have a nicer way to interact with these configurations via /proc?
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