[petsc-users] using intel mkl for optimized blas/lapack on amd nodes

[Klaij, Christiaan]

If the users are supposed to know this and act on it, perhaps an entry in the FAQs to raise awareness? With instruction how to check if the user's computing center automatically applies the trick.

Chris

_____
dr. ir. Christiaan Klaij | senior researcher
Research & Development | CFD Development
T +31 317 49 33 44 | https://urldefense.us/v3/__http://www.marin.nl__;!!G_uCfscf7eWS!bxo9uS0gHxRz9KO1sRNC2XOSjsx85ZEUIJkT1EPc6PG9lqapUvessDpxuTI0IWBGYwe8Xj5omRetklwCifJyIqw$ 
___________________________________
From: Pierre Jolivet <pierre at joliv.et>
Sent: Thursday, June 4, 2026 5:03 PM
To: Junchao Zhang
Cc: Richard Tran Mills; PETSc users list; Klaij, Christiaan
Subject: Re: [petsc-users] using intel mkl for optimized blas/lapack on amd nodes

You don't often get email from pierre at joliv.et. Learn why this is important<https://urldefense.us/v3/__https://aka.ms/LearnAboutSenderIdentification__;!!G_uCfscf7eWS!bxo9uS0gHxRz9KO1sRNC2XOSjsx85ZEUIJkT1EPc6PG9lqapUvessDpxuTI0IWBGYwe8Xj5omRetklwC_mMiWxU$ >
The libfakeintel.so<https://urldefense.us/v3/__http://libfakeintel.so__;!!G_uCfscf7eWS!bxo9uS0gHxRz9KO1sRNC2XOSjsx85ZEUIJkT1EPc6PG9lqapUvessDpxuTI0IWBGYwe8Xj5omRetklwCKZWvsBo$ > trick is as old as I can remember and it is available in all computing centers I’m using.
But it’s the duty of the users to preload it (again, on computing centers I have access to, module load’ing the MKL on AMD nodes automatically sets LD_PRELOAD).

Thanks,
Pierre

On 4 Jun 2026, at 4:52 PM, Junchao Zhang <junchao.zhang at gmail.com> wrote:

Richard, do you want to trick Intel?

--Junchao Zhang


On Thu, Jun 4, 2026 at 2:29 AM Klaij, Christiaan via petsc-users <petsc-users at mcs.anl.gov<mailto:petsc-users at mcs.anl.gov>> wrote:
I came across this issue:

https://urldefense.us/v3/__https://danieldk.eu/software/misc/intel-mkl-on-amd-zen__;!!G_uCfscf7eWS!bxo9uS0gHxRz9KO1sRNC2XOSjsx85ZEUIJkT1EPc6PG9lqapUvessDpxuTI0IWBGYwe8Xj5omRetklwCbUAVriM$ <https://urldefense.us/v3/__https://danieldk.eu/software/misc/intel-mkl-on-amd-zen__;!!G_uCfscf7eWS!fsSSG7b4cHz_fsk3H-3DI4kIopw4fIp1MW93aPTq10vZnZKOx1t7cEg2g4MbGyxZXr15OMM0jg0UU0q2p5ktYkQ$>

We do configure petsc with the intel mkl for optimized
blas/lapack using --with-blas-lapack-dir=${MKL_DIR}.

How much would this issue affect the performance of petsc on amd
nodes? Do you have the proposed workaround in place?

Chris
<image455803.png>
​​​​
dr. ir.         Christiaan       Klaij   |      senior researcher
Research & Development   |      CFD Development
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