microbenchmark

问题 Update: 2009-05-29 Thanks for all the suggestions and advice. I used your suggestions to make my production code execute 2.5 times faster on average than my best result a couple of days ago. In the end I was able to make the java code the fastest. Lessons: My example code below shows the insertion of primitive ints but the production code is actually storing strings (my bad). When I corrected that the python execution time went from 2.8 seconds to 9.6. So right off the bat, the java was

问题 This code is an adaptation of this other one... It is an ugly code but the question is about "how to do a benchmark". The new console.time function measure the "real execution time" or is it not so reliable? Is it really reliable for all browsers or can it change a bit? PS: is better to use Date.now() (or something like Unix terminal time ), external time reference? How to check "compiler optimizations" as ignoring a loop that do nothing? The benchmark below is supposed to measure the cost of

问题 Consider the following x86 assembly: ; something that sets rax mov rcx, [rdi] xor rax, rcx xor rax, rcx At the end of the sequence, rax has the same value as it had on entry, but from the point of view of the CPU its value depends on the value loaded from memory into rcx . In particular, subsequent use of rax won't start until that load and the two xor instructions complete. Is there any way to achieve this effect more efficiently than the two- xor sequence, e.g., with a single one-uop one

问题 I am learning how to microbenchmark things with JMH. I started with something seemingly simple: string concatenation for StringBuilder vs String += . From my understanding, I should make a State object that contains an instance of StringBuilder because I don't want to benchmark its constructor (nor do I want to an empty one every iteration anyway). Same goes for the String += test - I want a String object in my State to be concatenated with new strings. This is my code: @State(Scope.Thread)

问题 I find Google's micro benchmark project Caliper very interesting but the documentation is still (except some examples) quite non-existent. I have two different cases where I need to influence the command line of the JVMs Caliper starts: I need to set some fixed (ideally alternated between a few fixed values) -D parameters I need to specify some fixed (ideally alternated between a few fixed values) JVM parameters I saw some discussion about adding features like this but I could not conclude if

问题 I have a few questions on STREAM (http://www.cs.virginia.edu/stream/ref.html#runrules) benchmark. Below is the comment from stream.c. What is the rationale about the requirement that arrays should be 4 times the size of cache? * (a) Each array must be at least 4 times the size of the * available cache memory. I don't worry about the difference * between 10^6 and 2^20, so in practice the minimum array size * is about 3.8 times the cache size. I originally assume STREAM measures the peak memory

问题 Out of this SO post resulted a discussion when benchmarking the various solutions. Consider the following code # global environment is empty - new session just started # set up set.seed(20181231) n <- sample(10^3:10^4,10^3) for_loop <- function(n) { out <- integer(length(n)) for(k in 1:length(out)) { if((k %% 2) == 0){ out[k] <- 0L next } out[k] <- 1L next } out } # benchmarking res <- microbenchmark::microbenchmark( for_loop = { out <- integer(length(n)) for(k in 1:length(out)) { if((k %% 2)

问题 import java.util.ArrayList; import java.util.LinkedList; import java.util.List; public class CompareList { public static void main(String[] args) { List<Integer> ArrayList = new ArrayList<Integer>(); List<Integer> LinkedList = new LinkedList<Integer>(); doCalculations("ArrayList",ArrayList); doCalculations("LinkedList",LinkedList); } private static void doCalculations(String type,List<Integer> List){ for(int i=0;i<1E5;i++){ List.add(i); } Long start = System.currentTimeMillis(); /* To add

问题 I want to plot two-dimensional function z = f(x,y) using OpenGL and GLSL shaders. I'd like to map the value of function to color using a colormap, but some colormaps are expressed using HSL or HSV colorspace (for example hue maps). You can find (here and in other places) different alternative implementtions of hsv2rgb() in GLSL. How can I benchmark those shaders (those functions) to find out which one is fastest? 回答1: Implement all alternatives you want to try and apply the usual benchmark

问题 Can anyone explain why there is a performance difference between the following two segments? It's statistically significant that the second timer call reports a smaller number than the first timer call. My only thoughts would be that Netlogo could be caching the turtles in memory. Is this the expected behavior or is there a bug? to setup clear-all crt 100 let repetitions 10000 ;;Timing assigning x to self reset-timer repeat repetitions [ ask turtles [ let x self ] ] show timer ;;Timing