[$] Extending time slices for user-space locks

Steven Rostedt recently posted

a patch set that could help improve the performance of certain user-space
applications by giving the scheduler more context about when they are safe to
interrupt. The patch set lets programs request a small grace window
before they can be interrupted so that they can relinquish any locks, decreasing the
amount of time that other threads have to spend waiting. Rostedt shared
performance numbers suggesting that the patch might cut the amount of time spent
acquiring locks in half for some programs — although, since his test was
specifically tuned for this case, real-world projects should expect a somewhat
less dramatic improvement. The change received some pushback from scheduler
maintainer Peter Zijlstra, who objected to the patch set's approach.