Problems to start G-WAN - linux

Question

I try to install G-Wan on Ubuntu 12.04.1 LTS (x64).
I follow the fast instructions: http://gwan.com/download
When i execute $sudo ./gwan, shows me:
Floating point exception (core dumped)
Then i follow the slow instructions: http://www.as2.com/pdf/GWAN-Install-Manual-for-Ubuntu-12.04.pdf
but i have the same error.
I show you the errors of the logs:
apport.log
ERROR: apport (pid 13912) Mon Apr 29 13:42:56 2013: called for pid 13870, signal 8
ERROR: apport (pid 13912) Mon Apr 29 13:42:56 2013: executable: /opt/gwan_linux64-bit/gwan (command line "./gwan")
ERROR: apport (pid 13912) Mon Apr 29 13:42:56 2013: executable does not belong to a package, ignoring
syslog
Apr 29 13:43:48 ip-10-34-153-82 kernel: [1026847.541495] gwan[13914] trap divide error ip:427930 sp:7fff7208d7b8 error:0
Apr 29 13:43:53 ip-10-34-153-82 kernel: [1026852.993012] gwan[13958] trap divide error ip:427930 sp:7fffd2b82468 error:0
Please, Does anyone know what is the problem?
Install the program in my PC (Ubuntu 12.04.2 LTS) and works fine, i don't understand because in my PC works fine and in the server not.
Thanks for all and sorry, my english is bad.

Answer 1

The problem is that some newer versions of hypervisors insist to report ZERO CPU, and/or ZERO CPU Core, leading to a division by zero.
Since G-WAN is optimized for multicore architectures, it queries the CPUID instruction and the OS Kernel structures to check the platform architecture and the associated OS policies (number of online and allowed CPUs).
Other web servers are not affected because they expect users to manually configure and run as many instances as desired (hereby creating the duplicated resource allocations that G-WAN was designed to avoid).
Checking both the CPUID instruction and the Kernel structure was enough, until recently. Now, for any reason, the hypervisors use broken CPUID implementations and OS Kernel structure.
This issue is affecting hosting companies (VPS servers), and Amazon EC2 instances, among others.