[petsc-users] Would Mac OS version affect PETSc/C/C++ performance?

[Zou, Ling]

Hi Junchao,

Yeah, I have part of the log_view, for the same code, same version of PETSc (3.20), but two OS (Ventura vs. Sonoma).
Note that PETSc function call numbers are exactly the same.
I suspect that it’s just OS becomes slower, or maybe something related to the compiler.

-Ling

# of calls
Time spent (Ventura)
Time spent (Sonoma)
MatMult MF
20463
3.718600E+00
4.467800E+00
MatMult
20463
3.721000E+00
4.470500E+00
MatFDColorApply
2062
4.507000E+00
5.394600E+00
MatFDColorFunc
24744
4.472400E+00
5.356300E+00
KSPSolve
2062
3.569700E+00
4.262400E+00
SNESSolve
986
9.195900E+00
1.102000E+01
SNESFunctionEval
23575
4.268600E+00
5.161100E+00
SNESJacobianEval
2062
4.509300E+00
5.397500E+00


From: Junchao Zhang <junchao.zhang at gmail.com>
Date: Monday, August 19, 2024 at 10:04 PM
To: Zou, Ling <lzou at anl.gov>
Cc: petsc-users at mcs.anl.gov <petsc-users at mcs.anl.gov>
Subject: Re: [petsc-users] Would Mac OS version affect PETSc/C/C++ performance?
Do you have -log_view report so that we can know which petsc functions degraded? Or is it because compilers were different? --Junchao Zhang On Sun, Aug 18, 2024 at 6: 04 PM Zou, Ling via petsc-users <petsc-users@ mcs. anl. gov> wrote: Hi
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Do you have -log_view report so that we can know which petsc functions degraded?  Or is it because compilers were different?

--Junchao Zhang


On Sun, Aug 18, 2024 at 6:04 PM Zou, Ling via petsc-users <petsc-users at mcs.anl.gov<mailto:petsc-users at mcs.anl.gov>> wrote:
Hi all,

After updating Mac OS from Ventura to Sonoma, I am seeing my PETSc code having slightly-larger-than 10% of performance degradation (only in terms of execution time).
I track the number of major function calls, they are identical between the two OS (so PETSc is not the one to blame), but just slower.
Is this something expected, any one also experienced it?

-Ling
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