reftable: optimize I/O patterns
This patch series optimizes some I/O patterns that the reftable library uses:
-
Establish an stat(3P)-based caching mechanism to avoid re-reading "tables.list" all the time.
-
Convert the block source to use mmap(3P) instead of read(3P) to read data.
Combined these lead to a ~2.7x speedup when writing many refs.
Closes #197 (closed).
Edited by Patrick Steinhardt