Common trace problems in virtual environments
In the wake of our consulting activities we encountered a minor hurdle while running SpeedTrace in a large-application virtual machine environment. Since some of our customers also came across similar problems I thought it might be useful to let you in on the discourse.
Unexpectedly high overhead behavior …
While running SpeedTrace in such an environment we were suddenly confronted with an unusual overhead of 4-6 times the application’s normal speed – quite atypical of SpeedTrace’s reliably unintrusive behavior. It was as if there was some kind of echoing or reverberating effect that was interfering with the tracing procedure.
… is often caused by the VMware
Our developers found the VMware architecture to be at the root of the problem. VMware happens to be the software commonly used in virtual machine environments. Besides, it looks like we are going to have to cope with VMware overhead for some time to come … In any case, the VM overhead would invariably occur with any other profiler even as good as SpeedTRace which has been repeatedly acclaimed for its unusual unintrusiveness, accuracy and speed.
SpeedTrace solution to VM yields excellent results!
We are happy to announce, however, that our SpeedTrace development team has devised a rather simple and elegant solution to the problem. We tried it out and it works perfectly down to the usual couple of nanoseconds SpeedTrace normally generates in terms of its extremely low overhead rates.
SpeedTrace provides 100% accurate
readouts with zero overhead!
In fact, with SpeedTrace you can even objectively calculate and thus eliminate the already minute overhead delays to yield maximum accuracy! The new 3.3.34 version about to go online (but can be sent immediately on request) even takes a step further to show these net results automatically.
Don’t forget to use blackboxing, triggers and filters!
SpeedTrace’s overwhelming accuracy, however, should not distract your attention from the variety of time- and resource-saving blackboxing, trigger, and filtering functions that Speedtrace offers to speed up your whole trace and profiling process. To profile efficiently, third-party software components, for example, can and should be isolated through blackboxing even before you make your first trace. SpeedTrace is not only incredibly accurate, it is also stunningly fast!
For best results with virtual machines please consult our SpeedTrace support team.
