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RE: [PATCH] Fixed family and model detection for AMD CPU's
- From: "Pawar, Amit" <Amit dot Pawar at amd dot com>
- To: Joseph Myers <joseph at codesourcery dot com>
- Cc: Florian Weimer <fweimer at redhat dot com>, "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>
- Date: Fri, 20 Nov 2015 06:14:48 +0000
- Subject: RE: [PATCH] Fixed family and model detection for AMD CPU's
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-----Original Message-----
From: Pawar, Amit
Sent: Friday, November 06, 2015 10:32 AM
To: 'Joseph Myers'
Cc: Florian Weimer; libc-alpha@sourceware.org
Subject: RE: [PATCH] Fixed family and model detection for AMD CPU's
I have filed a bug with document reference. Please do check the link https://sourceware.org/bugzilla/show_bug.cgi?id=19214
This is only a correctness patch and can help in future for right selection of string and memory routines.
Amit Pawar
-----Original Message-----
From: Joseph Myers [mailto:joseph@codesourcery.com]
Sent: Thursday, November 05, 2015 6:20 PM
To: Pawar, Amit
Cc: Florian Weimer; libc-alpha@sourceware.org
Subject: RE: [PATCH] Fixed family and model detection for AMD CPU's
On Thu, 5 Nov 2015, Pawar, Amit wrote:
> Hi Florian,
>
> This is a correctness patch where family and model detection was wrong.
That doesn't answer the question. What do you mean by "wrong"? What is the background documentation that shows that the proposed change makes the logic correct?
A proper explanation might be along the lines of "processor X reports values A, B, C from CPUID; the existing code follows paths P and Q that wrongly identify it as processor Y, but, as explained in document R (URL), CPUID values on AMD processors should be interpreted as way S, meaning that the logic should change in way T". And with a bug filed in Bugzilla if this was user-visible (e.g. inappropriate function implementations being selected in glibc because of the wrong choices).
--
Joseph S. Myers
joseph@codesourcery.com