<html><body><p><tt><font size="2">"Klaus Heinrich Kiwi" <klaus@linux.vnet.ibm.com> wrote on 03/08/2021 12:48:28 PM:<br><br>> From: "Klaus Heinrich Kiwi" <klaus@linux.vnet.ibm.com></font></tt><br><tt><font size="2">> To: Haren Myneni/Beaverton/IBM@IBM</font></tt><br><tt><font size="2">> Cc: skiboot@lists.ozlabs.org, George Wilson/Austin/IBM@IBM</font></tt><br><tt><font size="2">> Date: 03/08/2021 12:48 PM</font></tt><br><tt><font size="2">> Subject: Re: [Skiboot] NX crypto on POWER9</font></tt><br><tt><font size="2">> <br>> <br>> <br>> On 3/8/2021 3:39 PM, Haren Myneni wrote:<br>> > Klaus,<br>> > <br>> > NX crypto is not enabled and supported on P9 due to performance issues. Instead use SW instructions.<br>> > <br>> > George Wilson can give more information.</font></tt><br><br><tt><font size="2">We consider NX crypto deprecated in favor of the VMX crypto instructions. The Linux device driver</font></tt><br><tt><font size="2">for NX crypto hasn't been updated on many years. NX crypto has a number of characteristics that</font></tt><br><tt><font size="2">make it difficult or impossible achieve the theoretical performance levels from it. Our team is</font></tt><br><tt><font size="2">neither the first nor the last to arrive at that conclusion. I'd strongly recommend using the</font></tt><br><tt><font size="2">vector instructions rather than NX.</font></tt><br><tt><font size="2"><br>> > <br>> > Thanks<br>> > haren<br>> <br>> Haren,<br>> <br>> thanks for your answer, but perhaps we need a bit more to go on?<br>> <br>> From what I could understand, Léo is really looking for the specification for NX crypto? Sometimes the use-case he <br>> has has better performance characteristics using those.. I don't think anyone is requesting Official IBM support here..<br>> <br>> -Klaus<br>> <br>> <br>> <br>> -- <br>> Klaus Heinrich Kiwi <klaus@linux.vnet.ibm.com><br></font></tt><BR>
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