> the main RW lock in folly, tries to shard them by core when it detects contention That's very interesting. I dealt with the scenario where I had to scale the

> the main RW lock in folly, tries to shard them by core when it detects contention That's very interesting. I dealt with the scenario where I had to scale the hash-map to support 1k-5k concurrent readers and a few sporadic writers. I ended up sharding the hash-map with each one using the RW lock to guard the access to the underlying data. This essentially declined the contention within the RW lock itself, or at least I wasn't able to measure it.