Why is my rsync transfer slow?

[dbonde+forum+rsync.lists.samba.org at gmail.com]

On 2016-01-21 15:00, Kevin Korb wrote:
 > First, don't use -z on a local copy.  It will only make rsync slower
 > for no reason at all.

Thanks. Hadn't thought about that. I just copied most from the spelled 
out "archive" list of switches. But is rsync so "stupid" that it really 
considers z for a local transfer?

 > Second, 45 million files means 90 million calls to stat().  This will
 > take a while even if nothing needs copying.

Hmm, is there a way to benchmark how long time it takes to do a stat() 
call?

And still, why is it so much slower than Finder? Finder is dog when it 
comes to file operations. Rsync (and cp) is usually many times faster.