How can I benchmark C code easily?
Use the function clock() defined in time.h: startTime = (float)clock()/CLOCKS_PER_SEC; /* Do work */ endTime = (float)clock()/CLOCKS_PER_SEC; timeElapsed = endTime – startTime;
benchmarking
LINQ Ring: Any() vs Contains() for Huge Collections
Contains() is an instance method, and its performance depends largely on the collection itself. For instance, Contains() on a List is O(n), while Contains() on a HashSet is O(1). Any() is an extension method, and will simply go through the collection, applying the delegate on every object. It therefore has a complexity of O(n). Any() … Read more
How to measure code performance in .NET?
The Stopwatch class, available since .NET 2.0, is the best way to go for this. It is a very high performance counter accurate to fractions of a millisecond. Take a look at the MSDN documentation, which is pretty clear. EDIT: As previously suggested, it is also advisable to run your code a number of times … Read more
Why is looping over range() in Python faster than using a while loop?
see the disassembly of python byte code, you may get a more concrete idea use while loop: 1 0 LOAD_CONST 0 (0) 3 STORE_NAME 0 (i) 2 6 SETUP_LOOP 28 (to 37) >> 9 LOAD_NAME 0 (i) # <- 12 LOAD_CONST 1 (100000000) # <- 15 COMPARE_OP 0 (<) # <- 18 JUMP_IF_FALSE 14 (to … Read more
Is there any simple way to benchmark Python script?
Have a look at timeit, the python profiler and pycallgraph. Also make sure to have a look at the comment below by nikicc mentioning “SnakeViz“. It gives you yet another visualisation of profiling data which can be helpful. timeit def test(): “””Stupid test function””” lst = [] for i in range(100): lst.append(i) if __name__ == … Read more
Spark: Inconsistent performance number in scaling number of cores
Theoretical limitations I assume you are familiar Amdahl’s law but here is a quick reminder. Theoretical speedup is defined as followed : where : s – is the speedup of the parallel part. p – is fraction of the program that can be parallelized. In practice theoretical speedup is always limited by the part that … Read more
Comparing BSXFUN and REPMAT
Introduction The debate on whether bsxfun is better than repmat or vice versa has been going on like forever. In this post, we would try to compare how the different built-ins that ship with MATLAB fight it out against repmat equivalents in terms of their runtime performances and hopefully draw some meaningful conclusions out of … Read more
How to Calculate Execution Time of a Code Snippet in C++
You can use this function I wrote. You call GetTimeMs64(), and it returns the number of milliseconds elapsed since the unix epoch using the system clock – the just like time(NULL), except in milliseconds. It works on both windows and linux; it is thread safe. Note that the granularity is 15 ms on windows; on … Read more
Which is faster: multiple single INSERTs or one multiple-row INSERT?
https://dev.mysql.com/doc/refman/8.0/en/insert-optimization.html The time required for inserting a row is determined by the following factors, where the numbers indicate approximate proportions: Connecting: (3) Sending query to server: (2) Parsing query: (2) Inserting row: (1 × size of row) Inserting indexes: (1 × number of indexes) Closing: (1) From this it should be obvious, that sending one … Read more