SMP +Example

This example shows the differences between code running in a unicore environment +and in a multiprocessor environment.

Download

Click on the following link to download +the example: SmpExample.zip

Click: browse to view the example code.

Class summary

RThread - A handle to a thread.
RDbStoreDatabase - DBMS Store database implementation

Design and implementation

The example creates two +databases named DBforSMP1.db and DBforSMP2.db and three threads:

WriterThread1: +It creates the DBforSMP1.db database and writes integers to it. The thread +has the lowest priority amongst all the threads.
WriterThread2: +It creates the DBforSMP2.db database and writes some integers to it. The thread +has highest priority amongst all the threads.
ReaderThread: +It reads the two databases and prints the output to the console. It has normal +priority.

In a unicore enviroment, the threads are executed according to their +priorities. This means first WriterThread2, then ReaderThread and +finally WriterThread1 is executed. Hence ReaderThead can +only print the contents of the DBforSMP2.db in the console because DBforSMP1 +is empty. in an SMP environment, threads run simultaneously and ReaderThread can +print the contents of both the databases.

Building and configuring

To build the example:

The example builds an +executable called smpexample.exe in the standard location.
You can build the example +from your IDE or the command line.

If you use an IDE, import the bld.inf file +of the example into your IDE, and use the build command of the IDE.

If +you use the command line, open a command prompt, and set the current directory +to the source code directory of the example. You can then build the example +with the SBSv1 build tools with the following commands:

bldmake +bldfiles

abld build

How to use bldmake and How to use abld describe +how to use the SBSv1 build tools.

Running the example

To test the example in an SMP +environment, add crazyscheduling onin the epoc32\data\epoc.ini file. +This emulates SMP behaviour in the techview emulator. Execute the example +in both unicore and multiprocessor environment and see the difference. Run +the example following the instructions provided in the console.