[IMPALA-6656] Metrics for time spent in BufferAllocator

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: Impala 3.2.0
• Component/s: Backend
• Labels: observability resource-management
• Target Version: Impala 3.2.0
• Epic Color: ghx-label-5
• Assignee: Tim Armstrong
• Reporter: Tim Armstrong
• Created: 13/Mar/18 23:42
• Updated: 03/Dec/18 17:20
• Resolved: 03/Dec/18 17:20

Description

We should track the total time spent and the time spent in TCMalloc so we can understand where time is going globally.

I think we should shard them by CurrentCore() to avoid contention and get more granular metrics. We want a timer for the amount of time spent in SystemAllocator. We probably also want counters for how many times we go down each code path in BufferAllocator::AllocateInternal() (i.e. getting a hit immediately in the local area, evicting a clean page, etc down to doing a full locked scavenge).