Caching authentication requests?

[djczaski]

I asked this question awhile ago but got no responses.  I guess that means
its either majorly stupid or completely obvious.  I'm running on a
beaglebone and when I enable something like auth_pam the number of requests
I can handle drops from about 500 per second to about 30 which isn't
suitable.  Any kind of point would be help.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,233054,233534#msg-233534