[2531] in Kerberos
Re: Scalability issues with Kerberos
daemon@ATHENA.MIT.EDU (John Hascall)
Sat Jan 23 23:03:41 1993
Date: Sun, 24 Jan 1993 03:41:19 GMT
From: john@iastate.edu (John Hascall)
To: kerberos@shelby.Stanford.EDU
I wrote:
> Although the load isn't constant over 24 hours, it doesn't vary as much
> as you might think:
Marc Horowitz <marc@MIT.EDU> writes:
}I see a peak when 9-5'ers get in in the morning, and another peak when
}students get out of class. And the fact that students have no
}discernible daily cycle accounts of the 1000+ requests at every hour
}of the day. I doubt intel would have such a distribution.
Well, I did a little more work -- I added code in our Kerberos server to
measure the time from request-arrival to reply-departure. I'll let
it run Monday for some real data, but here's what the first 6 minutes
of running it this evening gave (yes, another gruesome ascii chart):
90+ * Time from Request to Reply
| * (in 256ths of a second)
80+ *
| *
70+ *
| *
C 60+ *
o | *
u 50+ *
n | *
t 40+ *
| * *
30+ * *
| * *
20+ * * *
| * * *
10+ * * *
| * * * * * * * * *
0+-*-*-*-*-*-+-+-+-*-*-*-*-*-+-+-+-*-+-+-+-*-*-*-*-*-*-*-*-*-*-*-*-*-
0 1 2 3 4 5 6 7 8 9 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2
As you can see, it generally takes our server (an 8MB DS2100 [~8 Specmarks]
with a not-very-fast RZ55 disk) about 6/256 (0.023) sec to service a request.
One might hypothesize that using a modern workstation as a Kserver you should
be able to handle more than 100 requests per second. I suppose if you needed
more oomph, you could rewrite the server to be multi-threaded (*shudder*).
John
--
John Hascall ``An ill-chosen word is the fool's messenger.''
Systems Software Engineer
Project Vincent
Iowa State University Computation Center + Ames, IA 50011 + 515/294-9551
