Use the excellent web-based stats viewer for memcache, phpMemcachedAdmin, within your WordPress admin. This plugin serves as a wrapper for phpMemcachedAdmin.
From its homepage, phpmemcacheadmin is a:
Graphic stand-alone administration for memcached to monitor and debug purpose
This program allows to see in real-time (top-like) or from the start of the server, stats for get, set, delete, increment, decrement, evictions, reclaimed, cas command, as well as server stats (network, items, server version) with googlecharts and server internal configuration
WP-phpMemcachedAdmin adds phpMemcachedAdmin to the wp-admin’s Tools menu. Only logged-in WP admins, or a user with the manage_options capability, can view and use it. Attempts to directly view phpMemcachedAdmin by viewing its index.php file in a browser will fail.
The proper use of this plugin requires that memcached is installed on the server.
The link above is a direct link to the downloadable .zip file available from its Github home WP-phpMemcachedAdmin.
Because I wanted to touch the phpMemcachedAdmin code as little as possible, I run phpMemcachedAdmin thru an iframe. For this reason, this plugin is not available in the WordPress plugin repository.
Lastly, this plugin is released under GPLv3, making it compatible with WordPress (GPLv2 or later) and phpMemcachedAdmin (Apache 2).