performance

cloud computing performance

will it be possible to scale cloud computing concept to millions of user across the world? will it degrade the performance ...

XNA - Merge sprites for better drawing performance?

Hello! I read somewhere that when rendering a lot of 3D objects one could merge these to form a giant mesh so that only one draw call would be made. Therefore letting the, quote: "GPU do its magic", while the CPU is free for other calls than draw. So to my question, would this be feasible to do in a 2D environment with performance in m...

Is there a way to get rows_examined in MySQL without the slow log?

I'm building some profile information for a home grown app. I'd like the debug page to show the query sent along with how many rows were examined without assuming that slow_log is turned on, let alone parsing it. Back in 2006, what I wanted was not possible. Is that still true today? I see Peter Zaitsev has a technique where you start ...

Odd performance degradation in application...

We have an application that is mixed .NET 2.0 and native C++. In our testing, we have a mode which can automatically loop through a set of projects. A project opens, runs, closes, repeat. Each of these steps requires creation/destruction of windows (winforms to be precise). Recently we've experienced some odd behavior in performance. Aft...

Millions of small graphics files and how to overcome slow file system access on XP

Hi, I'm rendering millions of tiles which will be displayed as an overlay on Google Maps. The files are created by GMapCreator from the Centre for Advanced Spatial Analysis at University College London. The application renders files in to a single folder at a time, in some cases I need to create about 4.2 million tiles. Im running it on...

Class Vs Pure Array Representation

We need to represent huge numbers in our application. We're doing this using integer arrays. The final production should be maxed for performance. We were thinking about encapsulating our array in a class so we could add properties to be related to the array such as isNegative, numberBase and alike. We're afraid that using classes, howe...

Direct memory access to the network card in java

Some modern network cards support Direct Memory Access for improved performance. How can I utilize this feature from Java? Does the JVM provide this automatically, or do I need to do an allocateDirect on the ByteBuffers that I am using to talk to that NIC? Does anyone have documentation that discusses this? ...

Web server performance/test tool

Hi,I'm looking for a tool that simply tests a web server which I developed an application on it. Tool must tell me that entire web server or a page in my application - can serve at most how many users - can use how much CPU - can measure transaction per second (TPS) Please do not confuse my question for a kind of http(s) listening t...

Are modern CPU caches optimized to deal with constant strides? Across threads?

Say I have a big array, and multiple threads reading from the array. Each thread iterates through the array by jumping a constant amount, but starts at a different offset. So thread 1 may start at element 0, then read elements 32, 64, 96, etc. But thread 2 starts at element 1, and read element 33, 65, 97, etc. (keeping in mind that an 'e...

How to improve performance with our Rails image model and attachment_fu?

I've been trying to improve performance our app. The worst performing area seems to be the creation of our Image model, which uses attachment_fu: class Image < Attachment ... has_attachment :content_type => :image, :max_size => 100.megabytes, :storage => :file_system, :path_prefix => 'public/uploaded/images', :thum...

Programmatically getting per-process disk io statistics on Windows?

I would like to display a list of processes (Windows, C++) and how much they are reading and writing from the disk in KB/sec. The Resource Monitor of Windows 7 has the ability so I should be able to do the same. However I have unable to find a relevant API-call or find anything in the perfmon counters. Could anyone point me in the dire...

Does anyone have any performance metrics of ADO.NET connection pooling vs. the create-and-destroy method?

I'm using WCF, SQL Server and ADO.NET. I'm looking at two implementation options for the data access layer. The Enterprise Library that uses connection pooling A custom solution that does not use connection pooling. Every time the database is accessed a connection is created, used and then destroyed. Option 2 looks like this: using ...

The timeout period elapsed prior to obtaining a connection from the pool

Our site works fine for 90% of the day, then during our peak hours when traffic is about twice as heavy as normal, everything slows down to a crawl. Page load times that are normally 1 second take 30 seconds. Checking our error logs, it looks like it may be a connection pool issue. We have 3 web servers connected to 1 sql server db. ...

For consistent tempo on iPhone, is there a better solution than system sounds?

Hi, I've been working on a metronome app for quite some time now. Following Apple'e sample Metronome application, I've been using a timer on a (high priority) background thread to play system sounds. My results are okay but far from perfect. Some issues that I face are: ~ the app doesn't really keep time, although it sounds like it doe...

Performance with XML and ListView

Hi, i have one performance problem with XML and ListView: i have XML file with about 12000 nodes (yes, it it very much, but all nodes are necessary). This file has the following structure: <?xml .... ?> <MyRootNode> <node name="name1" lang="en" artist="aaa" genre="dsdsds" dsadasd="dsdsd" /> ... <node name="name12000" lang="en" artist=...

Is it more efficient to compare ints and ints or strings and strings

I've got a program written in c# where there are a lot of comparisons between ints and strings. So for performance reasons I would just like to know which is more efficient? If we have: int a = 5; string b = "5"; if(a == int.Parse(b)) { } OR if(a.ToString() == b) { } ...

how to determine which PHP code opens MySQL connections that aren't getting closed

We have an application that is comprised of a couple of off the shelf PHP applications (ExpressionEngine and XCart) as well as our own custom code. I did not do the actual analysis so I don't know precisely how it was determined, but am not surprised to hear that too many MySQL connections are being left unclosed (I am not surprised bec...

High speed UDP receiver in MATLAB

I'd like to implement the receiving end of my system in MATLAB - this requires Gigabit Ethernet with sustained speeds of over 200Mb/sec. Using MATLAB's built-in UDP from the Instrument Control Toolbox does not appear to be sufficient. Are there any good alternatives? ...

Firebird 2.0 transaction SELECT performance

In Firebird 2.0, is using an explicit transaction faster on a SELECT command than executing the command with an implicit one? ...

Performance effect of enabling apache response time log directive

What affect will enabling the response time (%D) LogFormat directive have on apache performance? The response time is the time taken to serve a request in microseconds. Response time can be enabled like so: #LogFormat "%h %l %u %t \"%r\" %>s %b" # Default LogFormat LogFormat "%h %l %u %t \"%r\" %>s %b %D" # LogFormat including res...