Dynamic instrumentation systems have proven to be extremely valuable for program introspection, architectural simulation, and bug detection. Yet a major drawback of modern instrumentation systems is that the instrumented applications often execute several orders of magnitude slower than native application performance. In this paper, we present a novel approach to dynamic instrumentation where several non-overlapping slices of an application are launched as separate instrumentation threads and executed in parallel in order to approach real-time performance. A direct implementation of our technique in the Pin dynamic instrumentation system results in dramatic speedups for various instrumentation tasks - often resulting in orderof- magnitude performance improvements. Our implementation is available as part of the Pin distribution, which has been downloaded over 10,000 times since its release.