Greets-
We gots a few nutters in work who enjoy using
while(true) { //Code }
in their code. As you can imagine this maxes out the CPU. Does anyone know ways to reduce the CPU utilization so that other people can use the server as well.
The code itself is just constantly polling the internet for updates on sites. Therefore I’d imagine a little sleep method would greatly reduce the the CPU usage.
Also all manipulation is being done in String objects (Java) anyone know how much StringBuilders would reduce the over head by?
Thanks for any pointers
I’ll start off with your second question, I would like to agree with the rest that StringBuilder vs String is very much dependent on the particular string manipulations. I had “benchmarked” this once and generally speaking as the amount of new string allocations went up (usually in the form of concatenations) the overall execution time went up. I won’t go into the details and just say that StringBuilder turned out to be most efficient overtime, when compared to String, StringBuffer, String.format(), MessageFormat…
My rule of thumb is that whenever I wish to concatenate more than 3 string together I always use StringBuilder.
As for your first question. We had a requirement to bring CPU usage to 5%. Not an easy task. We used Spring’s AOP mechanism to add a Thread.sleep() to before any method execution of a CPU intensive method. The Thread.sleep() would get invoked only if some limit had been exceeded. I am sorry to say that the computation of this limit is not that simple. And even sorrier to say that I still have not obtained the permission to post it up on the net. So this is just in order to put you on an interesting but complicated track that has proven to work over time.