Questions related to improving application performance, this can be range from selection software architecture to selection of algorithms.

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6
votes
1answer
643 views

Is event sourcing ready for prime time? [closed]

Event Sourcing was popularized by LMAX as a means to provide speed, performance scalability, transparent persistence and transparent live mirroring. Before being rebranded as Event Sourcing, this type ...
9
votes
5answers
3k views

Improving performance for grepping over a huge file

I have FILE_A which has over 300,000 lines and FILE_B which has over 30 million lines. I created a Bash script that greps each line in FILE_A over in FILE_B and writes the result of the grep to a new ...
22
votes
6answers
17k views

Why is quicksort better than other sorting algorithms in practice?

This is a repost of a question on cs.SE by Janoma. Full credits and spoils to him or cs.SE. In a standard algorithms course we are taught that quicksort is O(n log n) on average and O(n²) in the ...
7
votes
6answers
3k views

Software Optimization vs. Hardware Optimization - what has the bigger impact?

I was wondering how software optimization and hardware optimization compare when it comes to the impact they have on speed and performance gains of computers. I have heard that improving software ...
-4
votes
6answers
3k views

Is having two conditions in an IF statement faster than having two separate IF statements?

I just wonder if having two conditions in an IF statement executes faster than having it separated into two like these: Single Statement, two conditions if ( (conditionA == true) && ...
124
votes
13answers
29k views

Should we avoid object creation in Java?

I was told by a colleague that in Java object creation is the most expensive operation you could perform. So I can only conclude to create as few objects as possible. This seems somewhat to defeat ...
5
votes
1answer
122 views

When to use shared libraries for a web framework?

tl;dr: I've found myself hosting a bunch of sites running on the same web framework (symfony 1.4). Would it be helpful if I moved all of the shared library code into the same directory and shared it ...
3
votes
6answers
643 views

How do I determine if my code is optimized?

I am only developer working on a project. The functionality that I have coded works to expectations(desired result) but since I am the only one I don't know if I can do anything better to it. How do I ...
3
votes
2answers
187 views

Patterns for integrating with a slow external service

Was hoping someone could provide some patterns/techniques/ideas to increase performance for the following scenario. Am integrating with an external ordering system via SOAP. The external system can ...
4
votes
6answers
510 views

Information about how much time in spent in a function, based on the input of this function

Is there a (quantitative) tool to measure performance of functions based on its input? So far, the tools I used to measure performance of my code, tells me how much time I spent in functions (like ...
4
votes
5answers
671 views

Would “Efficient C++” book be irrelevant now due to compiler improvements? [closed]

I am planning on purchasing this book to learn more about C++ programming with regards to fast code. However, the book was published in 1999 and I am worried most of it may be irrelevant now due to ...
2
votes
1answer
1k views

What metrics should be used to measure memory consumption of a program for performance test?

I am asked to provide performance statistics for a program, one of them being memory consumption. I noticed that in perfmon or in .NET API there is apparently many variable related to memory usage, ...
0
votes
1answer
318 views

Splitting an image into many pieces to improve perceived performance? Good or Bad? [closed]

Time to time, I have to work on a website that involves a huge background in size and resolution (1920 x 1080 in resolution, over 2mb in size). I've been using preloaders and it worked very well, ...
1
vote
7answers
9k views

Merge sort versus quick sort performance

I have implemented merge sort and quick sort using C (GCC 4.4.3 on Ubuntu 10.04 running on a 4 GB RAM laptop with an Intel DUO CPU at 2GHz) and I wanted to compare the performance of the two ...
3
votes
1answer
3k views

Magic square check for N×N matrix with minimum complexity

Is there any algorithm that works better than O(n²) to verify whether a square matrix is a magic one (e.g. such as sum of all the rows, cols and diagonally are equal to each other)? I did see someone ...
10
votes
4answers
9k views

How can I monitor the JVM memory in a proper way?

I'm thinking of how we do JVM memory monitor in a low overhead way in production environment even under busy hour. Suppose I have two tomcat app server in production, load balance set up behind them. ...
5
votes
5answers
2k views

Structuring database for multi-object “activity” and “following” functionalities

I am working on a web application which operate with different types of objects such as user, profiles, pages etc. All objects have unique object_id. When objects interact it may produce "activity", ...
0
votes
2answers
369 views

Desktop GUI loading slow

I am developing desktop based GUI (single form) using wxPython and loads it using remote citrix access from client private network. Suppose, the GUI has certain group of select and text boxes which ...
1
vote
7answers
4k views

Performance analysis of C++ programs [closed]

How can I measure the performance of my C++ programs using C++? Specific metrics I want to measure are: Memory used (space) Duration taken (time)
0
votes
2answers
189 views

How can describe slow connection issues?

I have been working on a website containing 3d maps, virtual 3d tours, etc. All of the content is large like images and video. The problem is the site performs well under normal speed connections but ...
-1
votes
2answers
245 views

How should I group these variables?

I have a shape that will be defined by: char s_type; char color; double height; double width; These variables are scanned in from a request string sent to my server and passed into my printing ...
4
votes
1answer
338 views

Inexpensive generation of hierarchical unique IDs

My application is building a hierarchical structure like this: root = { 'id': 'root', 'children': [ { 'name': 'root_foo', 'children': [] }, { 'id': 'root_foo2', 'children': [ { ...
17
votes
2answers
12k views

Writing low latency Java [closed]

Are there any Java-specific techniques (things which wouldnt apply to C++) for writing low latency code, in Java? I often see Java low latency roles and they ask for experience writing low latency ...
2
votes
1answer
2k views

Improving performance for web scraping code

I have a website in which the code scrapes other websites for getting the accurate data. While the code works good but there a decent lag in performance because the code firsts downloads the html ...
5
votes
4answers
2k views

JSF for an internet facing, high traffic web application

I, perhaps, made a wrong choice of going with a Component-based Framework like JSF for an internet facing, high traffic web application. Development with JSF has although been easier but what I fear ...
7
votes
4answers
694 views

Is there a performance benefit to using immutable objects in a scripting language?

As I understand it, writing your objects in an immutable style can help the performance of your program for compiled languages, as the compiler tends to rewrite your code in single static assignment ...
4
votes
2answers
162 views

Is performance testing applicable to a QA or business user testing?

Performance testing is something that I, as a developer do when optimizing. However, if the change is purely optimization, should the QA or business user perform their own performance testing? I would ...
8
votes
2answers
2k views

Eclipse runs my java program 6 times faster… Can I achieve this performance without using it?

I've written a java program that generates all repetitive permutations based on the characters and the length given. When I execute my code in Eclipse, it generates a file with 1,000,000 permutations ...
0
votes
1answer
168 views

Data structure to use for complex lookups in an event engine?

What would be an optimal way to organize arbitrary data types into a structure that allows for complex (non-index based) lookups into the data without performing full loop-through's? For a little ...
3
votes
7answers
216 views

Throwing an Exception if a Query Doesn't Use an Index

I'm working on a largish webapp that was developed by several other programmers and I keep running into performance issues caused by poorly written SQL queries and queries that don't use an index. ...
1
vote
4answers
2k views

How do I speed up XML parsing operation?

I currently have a php script set up to do some xml parsing. Sometimes the script is set as an on page include and other times it is accessed via an ajax call. The problem is the load time for this ...
6
votes
2answers
553 views

Session size management

From what I know, the session information is usually saved on the server. In Java the data is handled as a Map which I guess contains the a String identifier and an object reference which points to a ...
3
votes
2answers
191 views

Where can I find good example of techniques to compact data in-memory? [closed]

I'm writing a Java framework to manipulate a large amount of data in-memory, where many "cells" that are near each other will have the same value. I'm looking for algorithms and/or techniques ...
3
votes
1answer
204 views

How to optimize methodology to collect Market Data?

I am working on Application which goes and get's market data from different sources, I am using polling mechanism where vendor/broker put his data file and my application would go and hit that ftp ...
1
vote
1answer
215 views

Where is a good place to start to learn about custom caching in .Net

I'm looking to make some performance enhancements to our site, but I'm not sure exactly where to begin. We have some custom object caching, but I think that we can do better. Our Business We ...
33
votes
5answers
17k views

Performance of Scala compared to Java

First of all I would like to make it clear that this is not a language-X-versus-language-Y question to determine which is better. I have been using Java for a long time and I intend to keep using it. ...
9
votes
4answers
333 views

Is it a good idea to measure the performance of a method by using unit test timeout?

In a project where there are non-functional requirements which specify the maximum execution time for a specific action, QA must check the performance of this action on a dedicated machine using ...
5
votes
1answer
758 views

Coded ui to measure performance

I have been tasked with using coded UI to measure performance on a proprietary windows desktop application. The need is to measure how long it takes for the next page/screen to display after a user ...
6
votes
1answer
356 views

Should web browsers include popular web framework libraries?

What reasons are there for web browsers to not have a library of popular web frameworks. For example if a web page included jQuery, why shouldn't the browser have it's own static version, which is ...
15
votes
5answers
2k views

Resources on Writing Efficient C Code for Micro-controllers? [closed]

Serious help needed here. I love programming. I've been reading bunch of books(such as K&R) and articles/forums online for C language lately. Even tried looking into Linux code(although, i was ...
4
votes
3answers
611 views

Question about a “Benchmark” regarding Java and .NET

To get that out of the way - i am not asking about which platform is faster or try to start a flame war. Question: Why is the .NET version slower 5x in the first test ? The results i got were: .NET ...
2
votes
2answers
3k views

How can I separate the user interface from the business logic while still maintaining efficiency?

Let's say that I want to show a form that represents 10 different objects on a combobox. For example, I want the user to pick one hamburguer from 10 different ones that contain tomatoes. Since I want ...
9
votes
6answers
600 views

Examples of general purpose algorithms that have benefited from running on a GPU? [closed]

I am looking for examples of general purpose algorithms (meaning non-graphics related) that have been proven to run an order of magnitude faster on a GPU than on a CPU. I will use these examples to ...
3
votes
2answers
196 views

What percentage of code and runtime do you typically allow for testing?

When I write code, a certain amount of it is just for the purpose of logging, tracing, or otherwise "testing" what the program is doing. This not unit testing; this is not when it is running in ...
4
votes
2answers
2k views

InterviewStreet (Vertical Sticks) just a tip where to get started

Having a lot of trouble with this question in interviewstreet.com: Given array of integers Y=y1,...,yn, we have n line segments such that endpoints of segment i are (i, 0) and (i, yi). Imagine that ...
0
votes
3answers
110 views

Should I decompress zips before I archive?

I am writing a small personal archiving tool. I frequently work with a lot of client databases for short periods, what my tool will do is in overnight batch jobs it will detach the database and zip up ...
6
votes
3answers
3k views

What performance can we expect from std::string's c_str()? Always constant time?

I've been doing some needed optimizations lately. One thing I've been doing is changing some ostringstreams -> sprintfs. I'm sprintf'ing a bunch of std::strings to a c style array, ala char foo[500]; ...
0
votes
2answers
228 views

Algorithm for searching the neighbors neighbor of a directed graph

Is there an algorithm to search a directed graph (tree) for its neighbors neighbor? My current brute-force solution works as follows: for each node n: for each child c of n for each parent ...
6
votes
3answers
9k views

Practical size limits of a Hashtable and Dictionary in c#

What are the practical limits for the number of items a C# 4 Dictionary or Hashtable can contain and the total number of bytes these structures can reasonable contain. I'll be working with large ...
4
votes
1answer
550 views

Is there a formula to figure out the total execution time of sequential asyncronous processes?

I have a set of steps that need to run sequentially over a list of data. However each step only operates on a single piece of data at a time. Because of this, I can run the steps asynchronously. For ...