Tag: performance

53 votes
1 answers
973 views
What is the best way to set a register to zero in x86 assembly: xor, mov or and?

All the following instructions do the same thing: set %eax to zero. Which way is optimal (requiring fewest mac

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User demo
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asked 07 September, 2021
64 votes
21 answers
318 views
Is inline assembly language slower than native C++ code?

I tried to compare the performance of inline assembly language and C++ code, so I wrote a function that add tw

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Rudolf
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asked 07 September, 2021
56 votes
4 answers
2.9K views
Why would introducing useless MOV instructions speed up a tight loop in x86_64 assembly?

Background: While optimizing some Pascal code with embedded assembly language, I noticed an unnecessary MOV i

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Jesenia
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asked 07 September, 2021
49 votes
12 answers
1.3K views
Is 'switch' faster than 'if'?

Is a switch statement actually faster than an if statement? I ran the code below on Visual Studio 2010's

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Renaldo
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asked 07 September, 2021
63 votes
5 answers
1.6K views
Why does Java switch on contiguous ints appear to run faster with added cases?

I am working on some Java code which needs to be highly optimized as it will run in hot functions that are inv

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Kristopher
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asked 07 September, 2021
58 votes
11 answers
1.8K views
Why does C++ code for testing the Collatz conjecture run faster than hand-written assembly?

I wrote these two solutions for Project Euler Q14, in assembly and in C++. They implement identical brute forc

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Deedee
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asked 07 September, 2021
64 votes
11 answers
1.9K views
Replacing a 32-bit loop counter with 64-bit introduces crazy performance deviations with _mm_popcnt_u64 on Intel CPUs

I was looking for the fastest way to popcount large arrays of data. I encountered a very weird effect: Changin

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Daniel
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asked 07 September, 2021
62 votes
14 answers
600 views
Is < faster than <=?

Is if (a < 901) faster than if (a <= 900)? Not exactly as in this simple example, but there are slight p

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Trudy
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asked 07 September, 2021
58 votes
7 answers
1.9K views
Fastest way to determine if an integer is between two integers (inclusive) with known sets of values

Is there a faster way than x >= start && x <= end in C or C++ to test if an integer is between t

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Stacia
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asked 07 September, 2021
50 votes
3 answers
321 views
What is the runtime performance cost of a Docker container?

I'd like to comprehensively understand the run-time performance cost of a Docker container. I've fou

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Yolando
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asked 07 September, 2021
63 votes
2 answers
1.9K views
arrayfun can be significantly slower than an explicit loop in matlab. Why?

Consider the following simple speed test for arrayfun: T = 4000; N = 500; x = randn(T, N); Func1 = @(a) (3*a^

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Yolando
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asked 07 September, 2021
51 votes
12 answers
1.9K views
Why is MATLAB so fast in matrix multiplication?

I am making some benchmarks with CUDA, C++, C#, Java, and using MATLAB for verification and matrix generation.

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Wei
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asked 07 September, 2021
60 votes
8 answers
599 views
LINQ: Not Any vs All Don&apos;t

Often I want to check if a provided value matches one in a list (e.g. when validating): if (!acceptedValues.A

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Don
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asked 07 September, 2021
55 votes
16 answers
1.4K views
Is it better to call ToList() or ToArray() in LINQ queries?

I often run into the case where I want to eval a query right where I declare it. This is usually because I nee

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Adolfo
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asked 07 September, 2021
49 votes
10 answers
1.1K views
Which method performs better: .Any() vs .Count() > 0?

in the System.Linq namespace, we can now extend our IEnumerable's to have the Any() and Count() extension

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Luis
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asked 07 September, 2021
51 votes
2 answers
1K views
Unexpected outcome of node.js vs ASP.NET Core performance test

I am doing a quick stress test on two (kinda) hello world projects written in node.js and asp.net-core. Both o

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Clarice
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asked 07 September, 2021
55 votes
16 answers
1.5K views
numpy: most efficient frequency counts for unique values in an array

In numpy / scipy, is there an efficient way to get frequency counts for unique values in an array? Something

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Xavier
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asked 07 September, 2021
60 votes
11 answers
1.4K views
Most efficient way to map function over numpy array

What is the most efficient way to map a function over a numpy array? The way I've been doing it in my cur

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Lawanda
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asked 07 September, 2021
53 votes
7 answers
701 views
Why use AJAX when WebSockets is available?

I've been using WebSockets for a while now, I have chosen to create an Agile project management tool for

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Tuan
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asked 07 September, 2021
54 votes
12 answers
1.3K views
Is String.Format as efficient as StringBuilder

Suppose I have a stringbuilder in C# that does this: StringBuilder sb = new StringBuilder(); string cat = "ca

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Shanita
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asked 07 September, 2021