Big O notation is commonly used to describe algorithm performance. But modern hardware makes performance analysis much harder than it used to be. In this short article we give three interesting examples to illustrate the limits of big O notation.
All posts in Performance
Crash course introduction to parallelism: the algorithms
When it comes to performance, there are two ways to go: one is to improve the usage of the existing hardware resources, the other is to use the new hardware resources. We already talked a lot about how to increase the performance of your program by better using the existing resources, for example, by decreasing…
Making your program run faster in a multithreaded environment
We investigate the performance impact of multithreading.
2-minute read: the Magic Touch of Parallel Algorithms
We investigate a simple way to speed up std::sort from the standard library
2-minute read: What is faster, std::endl or ‘\n’?
A few days ago I wrote a small app to illustrate one of the articles I was preparing. Basically the program was loading a file from the hard disk, sorting it, and then outputting to another file only unique values (by omitting duplicates). The function for writing unique values to a file looks like this:…
Talk: The Price of Dynamic Memory in C and C++
Ivica Bogosavljević from Johny’s Software Lab gave a talk on November 26th, 2020 as part of C++ User Group Osnabrück related to the performance price the developers pay when they are using dynamic memory in C and C++.
Use explicit data prefetching to faster process your data structure
When processing (searching, inserting etc) your data structure, if you are accessing it in random-access fashion, the performance will suffer due to many data cache misses. Read on how to use the explicit data prefetching to speed up access to your data structure.
Multitime: a small utility to measure your program’s runtime
Multitime is a tool that you can use to repeat a command several times, and get additional information about its runtime: mean, standard deviation etc. Read this short article to get you started,
Excessive copying in C++ and your program’s speed
We talk about C++ and its weakness for temporary objects and excessive copying. We also give some tips on how to avoid them and make your program faster.
Make your programs run faster: avoid expensive instructions
We will talk about expensive instructions in modern CPUs and how to avoid them to speed up your program.