0
votes
2answers
61 views

Mobile App Development-Architecture/Platform: Main performance concern: device/UI responsiveness

I am currently investigating different alternatives for building a mobile instant messaging application for iOS and Android, using an XMPP server (probably ejabberd) as the back-end. Main requirements ...
8
votes
5answers
902 views

Are there technical limitations or language features that prevent my Python script from being as fast as an equivalent C++ program?

I'm a long-time Python user. A few years ago, I started learning C++ to see what it could offer in terms of speed. During this time, I would continue to use Python as a tool for prototyping. This, it ...
17
votes
4answers
574 views

How bad is it calling println() often than concatenating strings together and calling it once?

I know output to the console is a costly operation. In the interest of code readability sometimes it is nice to call a function to output text twice, rather than having a long string of text as an ...
3
votes
3answers
220 views

Data Oriented Design - impractical with more than 1-2 structure “members”?

The usual example of Data Oriented Design is with the Ball structure: struct Ball { float Radius; float XYZ[3]; }; and then they make some algorithm that iterates a std::vector<Ball> ...
21
votes
7answers
3k views

Writing in C for Performance? [closed]

I know I have quite frequently heard that C typically has a performance advantage over C++. I didn't really think anything else of it until I realized that MSVC doesn't even seem to support the newest ...
0
votes
2answers
213 views

Can this argument be enough?

We have two C++ classes named Important and Small The class Small use a few methods and attributes from the class Important, but not all. Since our application is performance critical, instead of ...
1
vote
3answers
3k views

C++ Performance vs. Java/C# [closed]

My understanding is that C/C++ produces native code to run on a particular machine architecture. Conversely, languages like Java and C# run on top of a virtual machine which abstracts away the native ...
1
vote
2answers
2k views

Is rewriting some Java code to C++ using JNI to improve performance a good idea? [closed]

I've tried rewriting some Java functions in C++ and called them using JNI. I observed that it takes longer time to execute the native C++ functions as compared to Java functions, due to the JNI ...
9
votes
3answers
3k views

Java Heap Allocation Faster than C++

I already posted this question on SO and it did ok. It was unfortunately closed though(only needs one vote to reopen) but someone suggested I post it on here as it is a better fit so the following is ...
1
vote
1answer
185 views

Improving the efficiency of containers with dynamically allocated objects

This is not strictly related to C++ but its type system serves to illustrate the problem well. Assume: We have a generic template Container<T> (such as a std::vector<T>) which stores an ...
0
votes
2answers
208 views

The best way of coding web system in term of performance [closed]

So far I've been using IPB and my custom scripts all coded in PHP but I am really disappointed of the long term performance of it. I would like to move to native coding, the learning time to put into ...
0
votes
2answers
1k views

How to find local maxima in matrices?

I need to develop an algorithm for finding all the local maxima in a two-dimensional array: how to search for local maxima in the the most efficient way? Are there algorithms about it? Moreover, the ...
1
vote
1answer
723 views

Performance overhead of standard containers and boost [closed]

Adap.TV has chosen C++ to develop their software. However, they've decided not to use the standard containers1 and boost for performance reasons, as they've blogged about it in the following article: ...
4
votes
2answers
1k views

Performance and other issues with using floating point types in C++

Being interested in C++ performance programming there is one aspect I really have no clue about- and that is the implications of using floating point calculations vs doubles vs normal integer ...
0
votes
4answers
675 views

Read K&R before learning low latency C++?

I have never really done a large amount of C programming but am in the middle of teaching myself low latency C++. Would it do more harm than good to read the K&R C programming book? I am a bit ...
1
vote
2answers
748 views

C++ Typecasting VS performance

Let's say we're designing a video game. We have some sprites on the map and we want to call some method of the particular sprite at some particular position. We are using one broadly-known C++ ...
6
votes
3answers
738 views

A question regarding linked list vs vector insert/remove results comparison

I was reading this blog post: http://kjellkod.wordpress.com/2012/02/25/why-you-should-never-ever-ever-use-linked-list-in-your-code-again/ and I found there a code to run: http://ideone.com/62Emz ...
7
votes
4answers
8k views

What is the point of using lists over vectors, in C++?

I've run 3 different experiments involving C++ lists and vectors. Those with vectors proved more efficient, even when a lot of insertions in the middle were involved. Hence the question: in which ...
4
votes
4answers
230 views

What performance topics should I be aware of? [closed]

When coding performance-critical portions of code (not necessarily large, but code that gets executed a lot), what topics should I be aware of/take into account. I'm already fairly familiar with ...
4
votes
2answers
5k views

Low Latency Unix/Linux

Most low latency/high frequency programming jobs (based on job specs) appear to be implemented on unix platforms. In a lot of the specs they make particular request for people with "low latency linux" ...
3
votes
2answers
715 views

Memory management for fast message passing between threads in C++

Suppose there are two threads, which communicate by asynchronously sending data messages to each other. Each thread has some kind of message queue. My question is very low level: What can be expected ...
4
votes
4answers
511 views

Having error codes option in C++ library for performance

I have written an open source and cross-platform C++ File Library which have exception and error codes. Exceptions can be disabled when the program is running. In that case, the user have to check the ...
11
votes
8answers
1k views

Does low latency code sometimes have to be “ugly”?

(This is mainly aimed at those who have specific knowledge of low latency systems, to avoid people just answering with unsubstantiated opinions). Do you feel there is a trade-off between writing ...
8
votes
7answers
1k views

Is Java much harder to “tweak” for performance compared with C/C++?

Does the "magic" of the JVM hinder the influence a programmer has over micro-optimisations in Java? I recently read in C++ sometimes the ordering of the data members can provide optimizations ...
81
votes
11answers
21k views

What backs up the claim that C++ can be faster than a JVM or CLR with JIT? [closed]

A reoccurring theme on SE I've noticed in many questions is the ongoing argument that C++ is faster and/or more efficient than higher level languages like Java. The counter-argument is that modern JVM ...
5
votes
5answers
639 views

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

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 ...
0
votes
7answers
3k 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)
6
votes
3answers
2k 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]; ...
20
votes
6answers
3k views

C++ Renaissance - marketing slogan? [duplicate]

Possible Duplicate: What does the latest “C++ Renaissance” mean? Lately, I hear a lot about C++ Renaissance. What is that? C++ is currently undergoing a renaissance. This ...
54
votes
14answers
9k views

Why would it ever be possible for Java to be faster than C++?

Sometimes Java outperforms C++ in benchmarks. Of course, sometimes C++ outperforms. See the following links: http://keithlea.com/javabench/ ...
13
votes
5answers
6k views

JIT compiler for C, C++, and the likes

Is there any just-in-time compiler out there for compiled languages, such as C and C++? (The first names that come to mind are Clang and LLVM! But I don't think they currently support it.) ...