performance

One large file or multiple small files?

I have an application (currently written in Python as we iron out the specifics but eventually it will be written in C) that makes use of individual records stored in plain text files. We can't use a database and new records will need to be manually added regularly. My question is this: would it be faster to have a single file (500k-1Mb...

CUDA: Memory copy to GPU 1 is slower in multi-GPU

My company has a setup of two GTX 295, so a total of 4 GPUs in a server, and we have several servers. We GPU 1 specifically was slow, in comparison to GPU 0, 2 and 3 so I wrote a little speed test to help find the cause of the problem. //#include <stdio.h> //#include <stdlib.h> //#include <cuda_runtime.h> #include <iostream> #include <f...

Android - Declarative vs Programmatic UI

Has anyone seen or compiled benchmarks comparing declarative (XML) versus programmatically created UI's in Android? There are things that Google has done to speed up the declarative approach, but you still do have the layout inflation step done at runtime. Have you ever switched (or considered) changing your UI from declarative to prog...

When should I open and close a website's cached WCF proxy?

I've browsed around the other articles on StackOverflow that relate to caching WCF proxies for reuse, and I've read this article explaining why I should explicitly open the proxy before calling anything on it. I'm still a little hazy on the best implementation details. My question is: when should I open and close proxies for service ca...

What native C++ profiling tool do you suggest?

Can anyone suggest a performance analysis tool that runs on win32 on a native c++ app? How about one that runs on Windows Mobile? Thank you. ...

Hashtable is that fast

Hi s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]. Is the hash function of the java string, I assume the rest of languages is similar or close to this implementation. If we have hash-Table and a list of 50 elements. each element is 7 chars ABCDEF1, ABCDEF2, ABCDEF3..... ABCDEFn If each bucket of hashtable contains 5 strings (I think th...

Varying performance of MSVC release exe

Hello everyone, I am curious what could be the reason for highly varying performance of the same executable. Sometimes, I run it and it takes 20 seconds and sometimes it is 110. Source is compiled with MSVC in Release mode with standard options. The code is here: vector<double> Un; vector<double> Ucur; double *pUn, *pUcur; ... // time...

What is the complexity of OrderedDictionary?

Hi No one said that OrderedDictionary is having two copies of elements, one in a hashtable and other in a list, I can't find complexity measurements at MSDN for OrderedList. thanks ...

Problem with WPF perfomance.

I have form which has many tabs. Every tab has many controls textboxes, comboboxes, datagrids and e .t.c. I bind form to one data source in such way this.DataContext=MyClassInstance But with this way my form opening very slow. about one minute. When I comment above code, form opens very quickly. All My controls I bound to the class...

GWT ScrollTable performance problem

Hey all, I'm having a little performance problem with the gwt (incubator) ScrollTable. It's rendering really slow. Not even when I'm loading a lot of data - it happens already with a few rows. Or is it possible that the deserializing of the data takes so long? I'm using GWT 2.0 and IE. Maybe someone has the same problem or a solution ...

Which of these choices is the better design for drawing objects?

What would be a better parctice, writing the drawing method inside the GameObject class or in the Game class? GameObject obj = new GameObject(); obj.Draw(); Or GameObject obj = new GameObject(); DrawGameObject(obj); ...

How to get the size of a binary tree ?

I have a very simple binary tree structure, something like: struct nmbintree_s { unsigned int size; int (*cmp)(const void *e1, const void *e2); void (*destructor)(void *data); nmbintree_node *root; }; struct nmbintree_node_s { void *data; struct nmbintree_node_s *right; struct nmbintree_node_s *left; }; So...

Mysql Performance Question - Essentially about normalizing efficiency

Hi there. Just a quick question about database performance. I'll outline my site purpose below as background. I'm creating a dictionary site that saves the words users define to a database. What I'm wondering is whether or not to create a words table for each user or to keep one massive words table. This site will be used for entire sch...

Database structure for ecommerce site

Hey Guys, I have been tasked with designing an ecommerce solution. The aspect that is causing me the most problems is the database. Currently the site consists of 10+ country based shops each with their own database (all residing on the same mysql instance). For the new site I'd rather all these shop databases be merged into one da...

Why aren't we programming on the GPU?

So I finally took the time to learn CUDA and get it installed and configured on my computer and I have to say, I'm quite impressed! Here's how it does rendering the Mandelbrot set at 1280 x 678 pixels on my home PC with a Q6600 and a GeForce 8800GTS (max of 1000 iterations): Maxing out all 4 CPU cores with OpenMP: 2.23 fps Running the...

Task Manager: CPU usage history

I bougth recently a server with 2 x X5550, they are quad (4 cores each) total 8 cores If I check the task manager it shows in the CPU usage history 16 diagrams, Should't it be 8 cause I have 2 processors with quad? or the diagrams maybee shows the Threads of the CPU? ...

Best practice for defining CSS rules via JavaScript

I'm loading a stylesheet that is only required when javascript is enabled. More to the point, it mustn't be present if JavaScript is disabled. I'm doing this as soon as possible (in the head) before any javascript libraries are loaded. (I'm loading all scripts as late as possible). The code for loading this stylesheet externally is simpl...

Distributing cpu-bound compression jobs to multiple computers?

The other day I needed to archive a lot of data on our network and I was frustrated I had no immediate way to harness the power of multiple machines to speed-up the process. I understand that creating a distributed job management system is a leap from a command-line archiving tool. I'm now wondering what the simplest solution to this t...

How do I track down sporadic ASP.NET performance problems in a production environment?

I've had sporadic performance problems with my website for awhile now. 90% of the time the site is very fast. But occasionally it is just really, really slow. I mean like 5-10 seconds load time kind of slow. I thought I had narrowed it down to the server I was on so I migrated everything to a new dedicated server from a completely di...

How can I get page faults statistics from kernel

Hello How can I get page faults statistics from kernel for my application while it is running? What about other events, like inter-cpu migrations count in SMP nodes, or number of context switches? I want to count such events for various small parts of the program. Thanks. ...