Reply to post: Such an analysis would be useless

OpenBSD disables Intel’s hyper-threading over CPU data leak fears

Crazy Operations Guy

Such an analysis would be useless

The effects of hyperthreading vary quite a bit based on the workload you are feeding it. The simplest method would probably be to profile a day's worth of work, disable HT, the repeat the exact same workload to see if there is a performance difference.

The easiest way might be to build two systems exactly the same (Same hardware, OS, software, etc. but one has HT turned on and the other doesn't), then run some sort of mirroring device so that both machines get the exact same data and do the exact same work.

I've seen MySQL databases do everything from falling to pieces to flying like a speed demon with Hyperthreading in different states. I've seen it vary that much with the same data, but slightly different queries used to process the data. One of our web applications went from an application-based spin-lock structure to using MySQL's atomic operations, in this case disabling HT actually increased performance about 10-15% despite having half as many threads available.

POST COMMENT House rules

Not a member of The Register? Create a new account here.

  • Enter your comment

  • Add an icon

Anonymous cowards cannot choose their icon

Biting the hand that feeds IT © 1998–2021