benchmarking

Given a huge collection of objects, is there a performance difference between the the following? Collection.Contains : myCollection.Contains(myElement) Enumerable.Any : myCollection.Any(currentElement => currentElement == myElement) 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() is more flexible however since

Is there a simple library to benchmark the time it takes to execute a portion of C code? What I want is something like: int main(){ benchmarkBegin(0); //Do work double elapsedMS = benchmarkEnd(0); benchmarkBegin(1) //Do some more work double elapsedMS2 = benchmarkEnd(1); double speedup = benchmarkSpeedup(elapsedMS, elapsedMS2); //Calculates relative speedup } It would also be great if the library let you do many runs, averaging them and calculating the variance in timing! Joe Basically, all you want is a high resolution timer. The elapsed time is of course just a difference in times and the

I am working with Subsonic 2 more than 3 years now... After Linq appears and then Subsonic 3, I start thinking about moving to the new Linq futures that are connected to sql. I must say that I start move and port my subsonic 2 with SubSonic 3, and very soon I discover that the speed was so slow thats I didn't believe it - and starts all that tests. Then I test Linq2Sql and see also a delay - compare it with Subsonic 2. My question here is, especial for the linq2sql, and the up-coming dotnet version 4, what else can I do to speed it up ? What else on linq2sql settings, or classes, not on this

I want to log how long something takes in real walltime. Currently I'm doing this: startTime = time.time() someSQLOrSomething() print "That took %.3f seconds" % (time.time() - startTime) But that will fail (produce incorrect results) if the time is adjusted while the SQL query (or whatever it is) is running. I don't want to just benchmark it. I want to log it in a live application in order to see trends on a live system. I want something like clock_gettime(CLOCK_MONOTONIC,...), but in Python. And preferably without having to write a C module that calls clock_gettime(). Armin Ronacher That

The other day I was doing some Python benchmarking and I came across something interesting. Below are two loops that do more or less the same thing. Loop 1 takes about twice as long as loop 2 to execute. Loop 1: int i = 0 while i < 100000000: i += 1 Loop 2: for n in range(0,100000000): pass Why is the first loop so much slower? I know it's a trivial example but it's piqued my interest. Is there something special about the range() function that makes it more efficient than incrementing a variable the same way? kcwu see the disassembly of python byte code, you may get a more concrete idea use

How do I call clock() in C++ ? For example, I want to test how much time a linear search takes to find a given element in an array. #include <iostream> #include <cstdio> #include <ctime> int main() { std::clock_t start; double duration; start = std::clock(); /* Your algorithm here */ duration = ( std::clock() - start ) / (double) CLOCKS_PER_SEC; std::cout<<"printf: "<< duration <<'\n'; } An alternative solution, which is portable and with higher precision, available since C++11, is to use std::chrono . Here is an example: #include <iostream> #include <chrono> typedef std::chrono::high

In an answer , I've stated that unaligned access has almost the same speed as aligned access a long time (on x86/x86_64). I didn't have any numbers to back up this statement, so I've created a benchmark for it. Do you see any flaws in this benchmark? Can you improve on it (I mean, to increase GB/sec, so it reflects the truth better)? #include <sys/time.h> #include <stdio.h> template <int N> __attribute__((noinline)) void loop32(const char *v) { for (int i=0; i<N; i+=160) { __asm__ ("mov (%0), %%eax" : : "r"(v) :"eax"); __asm__ ("mov 0x04(%0), %%eax" : : "r"(v) :"eax"); __asm__ ("mov 0x08(%0),