Performance regression come again on dotnet 9 #111016
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Tagging subscribers to this area: @dotnet/area-system-numerics |
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I do measure a regression, but nowhere near what you're seeing (on Intel or AMD) This is due to an MSVC correctness bug that exists in native: https://developercommunity.visualstudio.com/t/MSVCs-sincos-implementation-is-incorrec/10582378 and thus .NET 9 was fixed to no longer use the The exact performance is a bit dependent on the input, but it should be pessimizing to approximately the same performance as if you invoked Intel
AMD
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I notice that your platform have avx512 support, but my laptop only got avx2. Or it might be a exclusive bug of 12/13/14th gen core CPU,lol As you say, I think I should call sin & cos seperately in the future, to aviod strange behaviour. thanks |
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Assigned to @PranavSenthilnathan for triage. |
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The 40x perf difference between .NET 9 and .NET 8 seems very high. When I run the benchmark on AMD I also see only a 2x slowdown like Tanner. Could you check that the only difference between the two benchmarks is the runtime version and nothing else? If you've confirmed that is not the issue, can you try changing Also, a small, single file console app repro of the issue (using stackalloc and |
I can confirm that I use NET8_0_OR_GREATER at my first post 3 weeks ago. I just try a small change at https://github.com/kingsznhone/VSOP2013.NET/blob/c4620771f065c1c17fbf50929c71ad00087f083b/VSOP2013.NET/Calculator.cs#L20 from Then everything going well at 2x slowdown
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So just to confirm - are these latest benchmark numbers with the following? #if NET8_0_OR_GREATER
_ = GetZero();
#endifIf you remove the |
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Fully Removed
Right after add .net9 target [MethodImpl(MethodImplOptions.NoInlining)]
private static Vector128<float> GetZero() => Vector128<float>.Zero;
......
#if NET8_0
_ = GetZero();
#endif
same code for top of the issue [MethodImpl(MethodImplOptions.NoInlining)]
private static Vector128<float> GetZero() => Vector128<float>.Zero;
......
#if NET8_0_OR_GREATER
_ = GetZero();
#endif
Last Modify [MethodImpl(MethodImplOptions.NoInlining)]
private static Vector256<float> GetZero() => Vector256<float>.Zero;
......
#if NET8_0_OR_GREATER
_ = GetZero();
#endif
Use sin & cos separately without GetZero() for (int n = 0; n < terms.Length; n++)
{
double u = terms[n].aa + terms[n].bb * tj;
double su = Math.Sin(u);
double cu = Math.Cos(u);
result += t[it] * (terms[n].ss * su + terms[n].cc * cu);
}
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Description
#95954
With temporary resolution in this issue . I add this segment to fix dotnet 8 performance regression. It makes performance back to 90% of dotnet 7
https://github.com/kingsznhone/VSOP2013.NET/blob/8a9e03fd734d9c29de788877724e32022b042d21/VSOP2013.NET/Calculator.cs#L151
Few days ago. I try dotnet 9 to run perf test. Same situation occor as before.
Ethier I apply that fix or not. Performance still very bad.
This line cause performance heavily drop as before.
(su, cu) = Math.SinCos(u);Data
``
BenchmarkDotNet v0.13.11, Windows 11 (10.0.22631.4602/23H2/2023Update/SunValley3)
12th Gen Intel Core i9-12950HX, 1 CPU, 16 logical and 16 physical cores
.NET SDK 9.0.101
[Host] : .NET 8.0.11 (8.0.1124.51707), X64 RyuJIT AVX2 [AttachedDebugger]
.NET 8.0 : .NET 8.0.11 (8.0.1124.51707), X64 RyuJIT AVX2
.NET 9.0 : .NET 9.0.0 (9.0.24.52809), X64 RyuJIT AVX2
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