[IMPALA-3136] Replace impala's SpinLock with one based on gutil spinlock

• Type: Improvement
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: impala 2.3
• Fix Version/s: Impala 2.6.0
• Component/s: Backend
• Target Version: Impala 2.6.0
• Assignee: Daniel Hecht
• Reporter: Daniel Hecht
• Created: 04/Mar/16 00:45
• Updated: 10/Mar/16 19:45
• Resolved: 10/Mar/16 19:44

Description

Our current spinlock implementation always busy spins. We've seen cases where this effectively causes priority inversion leading to very large lock wait times, e.g. IMPALA-3107.

We should switch to an adaptive spin-then-wait lock that first spins for a short time (in case the critical section is very short), and then automatically falls back to blocking. gutils has one that looks sane and I think as a bonus may keep contention stats.

Or we could see what the current version of boost/std mutex looks like. I think last we looked it always blocked which is why a custom SpinLock class was added.