From my initial testing this is very promising for a postgres server.
Benchmark-wise, a simple dd with an 8k blocksize gets ~200MB/s as
compared to ~140MB/s on the same hardware without the patch. Also, that
200MB/s seems to be unaffected by the dd blocksize, whereas without the
patch a 512k blocksize would get ~100MB/s. I'm now watching to see how
it does over a couple of days on real-world workloads.
Mike Stone