Signed-off-by: Vijay Bellur <vijay@gluster.com>
Signed-off-by: Vijay Bellur <vijay@dev.gluster.com>

BUG: 971 (dynamic volume management)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=971

Signed-off-by: Pranith Kumar K <pranithk@gluster.com>
Signed-off-by: Vijay Bellur <vijay@dev.gluster.com>

BUG: 1388 ()
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=1388

This patch adds a facility by which each translator
keeps track of the average latency of a FOP from
its point of view. That is, the duration between
the translator handing over the call to a lower-level
translator and the reply coming back.

The latency measurement is off by default, and can
be toggled by sending SIGUSR2 to the GlusterFS process.

Latency data is printed as part of the process state dump.

Signed-off-by: Vikas Gorur <vikas@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 268 (Add timing instrumentation code)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=268