[TriLUG] [Novalug] Comparing Clouds; A trivial test. (fwd)

[William Sutton]

This came across the NoVALUG list this morning.  I found it most 
interesting.

William Sutton

---------- Forwarded message ----------
Date: Sat, 26 Oct 2013 01:22:08 -0600
From: Maxwell Spangler <maxlists at maxwellspangler.com>
To: novalug <novalug at calypso.tux.org>
Subject: [Novalug] Comparing Clouds; A trivial test.


I spent some time working with Amazon, Rackspace and Google Compute Engine
clouds this week in order to port a little Linux script I'm working on.

I decided to do a simple, somewhat trivial experiment to compare cloud
quality on a very low-end.  I wanted to learn how each cloud would handle
the smallest of activities.  Let me stress that large, sophisticated cloud
applications may see very different results.

So I wrote a simple program in C to do several billion simple addition
computations.  No storage, no networking, no systems calls.  This is all
about how much time my cloud's virtual machine gets to do its job.

Control:  Debian 7.2 virtual machine in KVM virtual machine on my local
workstation.  The workstation is a 2010-era 4-core AMD Phenom II CPU with
12G of RAM and no other significant workloads.

root at debian72:~# time ./cputest
real 134m15.134s   [2.23 hours]
user 134m9.707s
sys 0m0.020s

____________________________________________________________________________


First test: Rackspace.  Unknown server with AMD Opteron 2.1GHz 4170 HE
"Lisbon" processor.  Similar to a 6-core version of my Phenom II.

[root at rackfree ~]# time ./cputest
real 192m41.034s  [3.20 hours]
user 192m8.815s
sys 0m2.852s

Not bad! Let's assume I'm on a shared machine with other VMs competing for
time and therefore cluttering up the CPU caches, causing context switches
and the hypervisor is taking IRQ activity for other system network and IO
calls.

____________________________________________________________________________


Second test: Amazon AWS.  Unknown server with Intel Sandy Bridge E5-2650 CPU
@ 2.0 Ghz.

89501.70user 6.95system 24:55:26elapsed 99%CPU (0avgtext+0avgdata
1440maxresident)k
0inputs+0outputs (0major+124minor)pagefaults 0swaps

OUCH!  The first time I attempted this, it hadn't finished nearly a day
later and my connection got dropped.  So I ran it again using 'nohup' and
caught the output.

The classic Unix 'sar' utility catches what's going on.  I hadn't seen the
"%steal" column before, but this was a perfect case where you'd want to
monitor it.  From the man page:

             %steal Percentage of time spent in involuntary wait
             by the virtual CPU or CPUs while the hypervisor was
             servicing another virtual processor."


Linux 3.4.62-53.42.amzn1.x86_64 (ip-999-999-999-999) 	10/24/2013 	_x86_64_(1 C
PU)

09:52:58 PM     CPU     %user     %nice   %system   %iowait    %steal     %i
dle
09:53:58 PM     all     11.58      0.00      0.01      0.00     88.40      0
.00
09:54:58 PM     all     24.46      0.00      0.03      0.00     75.51      0
.00
09:55:58 PM     all      7.62      0.00      0.00      0.00     92.38      0
.00
09:56:58 PM     all     13.71      0.00      0.00      0.00     86.29      0
.00
09:57:58 PM     all     12.00      0.00      0.02      0.00     87.99      0
.00


____________________________________________________________________________





This is exploratory testing of using a cloud for small workloads, not
rigorous scientific testing.

However, it's a simple and easy way to make observations about using a cloud
resource instead of something you control:

* Some cloud resources will definitely be over-committed and your
performance will vary greatly.

* Two similar virtual machine sizes on two different cloud providers may
provide vastly different results.

I hope you enjoyed this.  I did!

Cheers,


--
Maxwell Spangler
========================================================================
Linux System Administration / Virtualization / Development / Computing
Services
Photography / Graphics Design / Writing
Fort Collins, Colorado
http://www.maxwellspangler.com
-------------- next part --------------
_______________________________________________
Web Page:  http://lug.boulder.co.us
Mailing List: http://lists.lug.boulder.co.us/mailman/listinfo/lug
Join us on IRC: irc.hackingsociety.org port=6667 channel=#hackingsociety
-------------- next part --------------
_______________________________________________
Novalug mailing list
Novalug at calypso.tux.org
http://calypso.tux.org/mailman/listinfo/novalug