approx qps server CPU util
MySQL via SQL 105,000 %us 60% %sy 28%
memcached 420,000 %us 8% %sy 88%
MySQL via HandlerSocket 750,000 %us 45% %sy 53%
Verification of benchmarks
Percona Server now both SQL and NOSQL
Various PHP libraries via https://github.com/ahiguti/HandlerSocket-Plugin-for-MySQL
Anyway this seems like a major win. All the bits are in place for this to be used. Nice thing about HandlerSocket is it gets around some of the limitations of memcache; if it doesn't work then just use normal SQL commands.