UNIX for Dummies Questions & Answers

We have a single threaded application which is restricted by CPU usage even though there are multiple CPUs on the server, hence leading to significant performance issues. Is it possible to merge / combine multiple CPUs at OS level so it appear as a single CPU for the application?

Well we dont know much about your OS for a start...

Apologies for being vague . Wanted to know if this is possible in any of Linux or Unix platforms. We are using Red Hat Enterprise Linux Server release 5.8.

OK your application doesnt know how to take advantage of multi-threading, but that should not be an issue on a multi-core... Even One thread appl. can make usage of more than 1 cpu... not that you will have 2 cpu dedicated, but your application may pass from one to another depending of the load and so should gain on context switching...
So I believe its more a question of tuning... but for that youwould have to know what you application is doing and where it is stuck...

We know for sure that application is not able to use more than one CPU and the vendors has confirmed the same. There are other ways to increase usage of CPU multiple CPU( i.e. multi-instances) but this is not sufficient due to other business process level complications.

This is the reason why we are looking to increase processing power vertically (merged CPU) [if possible] than horizontally(multiple CPU).

Since you say you want to know if this is possible on *any* platform running unix or linux I guess I would need to say yes. If hyperthreading is on simply turn it off.

That I understand..
OK on HP-UX when I had this sort of issues, I used to dedicate a CPU to that application or user ... he would find himself as if on a single cpu box... only it will run at the speed of the cpu...
kernel params, to allow big - long processes to use all the cpu, I used to change the timeslice, but this is very tricky : You fall on badly written code, and you have lost control of your server... So although this can accelerate your application it has some terrible side effects, because the parameter affects all the system... I used to fine tune a kernel specificly for batches, and compile a kernel for that purpose, then its just a question of swaping kernel and reboot...

You have to accept the idea that 2 CPU 1GHz cannot do 1CPU@2GHz, and so will have to tune what you can, to reduce I/O , disk access etc.. and to remember the better is the ennemy of Good...

You are left analysing why you have performance issues and try to find workarounds, and I tell you there are