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Date: Wed, 16 Nov 2022 16:33:59 +0100
From: Jan Hubicka <hubicka@ucw.cz>
To: "amonakov at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
Cc: gcc-bugs@gcc.gnu.org
Subject: Re: [Bug target/87832] AMD pipeline models are very costly size-wise
Message-ID: <Y3UC5+03uceRbtug@kam.mff.cuni.cz>
References: <bug-87832-4@http.gcc.gnu.org/bugzilla/>
 <bug-87832-4-o99BRaYD0C@http.gcc.gnu.org/bugzilla/>
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> 
> Do you mean we should fix modeling of divisions there as well? I don't have
> latency/throughput measurements for those CPUs, nor access so I can run
> experiments myself, unfortunately.
> 
> I guess you mean just making a patch to model division units separately,
> leaving latency/throughput as in current incorrect models, and leave it to
> manufacturers to correct it? Alternatively, for AMD Bobcat and Bulldozer we
> might be able to crowd-source it eventually.
Actually for older cores I think the manufacturers do not care much.  I
still have a working Bulldozer machine and I can do some testing.
I think in Buldozer case I was basing the latency throughput on data in
Agner Fog's manuals.  How do you test it?
Honza