Enable processor-specific optimizations when available:
The SConstruct is modified to enable processor specific optimizations on clang and gcc toolchains. This improves the performance of RocksDB's CRC function
Avoid zero initialization of Blob
Add repeatable NodeStore timing benchmark:
The timing test is changed to overcome in-memory caching performed by Backend implementations. Additional command line arguments allow configuration of test parameters such as the number of objects. The test is modified to represent more relevant metrics.
Add new RocksDBQuickFactory for benchmarking:
This new factory is intended for benchmarking against the existing RocksDBFactory and has the following differences.
* Does not use BatchWriter
* Disables WAL for writes to memtable
* Uses a hash index in blocks
* Uses RocksDB OptimizeFor… functions