linux-kernel - Re: [PATCH 01/14] x86/cqm: Intel Resource Monitoring Documentation

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Date:   Fri, 23 Dec 2016 13:41:54 -0800 (PST)
From:   Shivappa Vikas <vikas.shivappa@...el.com>
To:     Peter Zijlstra <peterz@...radead.org>
cc:     Shivappa Vikas <vikas.shivappa@...el.com>,
        Vikas Shivappa <vikas.shivappa@...ux.intel.com>,
        linux-kernel@...r.kernel.org, x86@...nel.org, tglx@...utronix.de,
        ravi.v.shankar@...el.com, tony.luck@...el.com,
        fenghua.yu@...el.com, andi.kleen@...el.com, davidcc@...gle.com,
        eranian@...gle.com, hpa@...or.com
Subject: Re: [PATCH 01/14] x86/cqm: Intel Resource Monitoring Documentation

On Fri, 23 Dec 2016, Peter Zijlstra wrote:
>
> Also, the 'whoops you ran out of RMIDs, please reboot' thing totally and
> completely blows.

Well, this is really a hardware limitation. User cannot monitor more events on a 
package than # of RMIDs at the *same time*. The 10/14 reuses the RMIDs that are 
not monitored anymore. User can monitor more events once he stops monitoring 
some..

So we throw error at the read (LAZY mode) or open(NOLAZY mode) ..

>
>