This patch introduces "BATCH" mode.

This patch introduces "BATCH" mode.

In this mode, a client can feed multiple commands to rrdcached without
waiting for acknowledgement.  This permits multiple commands to be sent
for each read()/write().  This can dramatically increase the command
throughput by increasing the amount of work done per system call.

It enables over 100k updates/second with no CPU
utilization due to the reduced system calls.

-- kevin brintnall

git-svn-id: svn://svn.oetiker.ch/rrdtool/trunk/program@1581 a5681a0c-68f1-0310-ab6d-d61299d08faa