Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Fri, 23 Apr 2021 16:29:41 +0200
From:   Borislav Petkov <bp@suse.de>
To:     Calvin Walton <calvin.walton@kepstin.ca>
Cc:     Chen Yu <yu.c.chen@intel.com>, Terry Bowman <terry.bowman@amd.com>,
        lenb@kernel.org, linux-pm@vger.kernel.org,
        linux-kernel@vger.kernel.org, wei.huang2@amd.com, aros@gmx.com,
        rui.zhang@intel.com
Subject: Re: [PATCH v2] tools/power turbostat: Fix RAPL summary collection on
 AMD processors
Message-ID: <YILZ1aNVrAa9vx79@zn.tnic>
References: <20210419195812.147710-1-terry.bowman@amd.com>
 <20210420020336.GA386151@chenyu-desktop>
 <20210420080701.GA2326@zn.tnic>
 <20210420131541.GA388877@chenyu-desktop>
 <4cbb1eff77de1e843912267ade4686cfa1acd610.camel@kepstin.ca>
 <20210420143754.GA390118@chenyu-desktop>
 <5cf35f3742d1181421d955174b1aa9434d042c96.camel@kepstin.ca>
 <20210423121607.GA426003@chenyu-desktop>
 <20210423121934.GC24710@zn.tnic>
 <23f75aaf3d37cbad6f8ed7bd970434e4a2dc388e.camel@kepstin.ca>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <23f75aaf3d37cbad6f8ed7bd970434e4a2dc388e.camel@kepstin.ca>
Precedence: bulk

On Fri, Apr 23, 2021 at 10:00:14AM -0400, Calvin Walton wrote:
> So, there's two problems with that:
>    1. This function needs to be able to return an error value that cannot be
>       confused with a valid MSR. This is currently done by returning a
>       negative number. If an unsigned value is used, a different way of
>       indicating errors needs to be written.
>    2. We are not using CPU instructions to access MSRs direction. Instead
>       they are being read from /dev/msr. So the "offset" value is actually a
>       seek into the /dev/msr file (using pread), and thus is of type off_t.

Ah right, that's the /dev/msr thing. Then off_t is correct, forget what
I said.

Thx.

-- 
Regards/Gruss,
    Boris.

SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg