From: Lionel Bouton <lionel-subscription@...>
Date: 2008-02-22T02:13:52+09:00
Subject: Re: [QUIZ #157] 32bit vs 64bit vs UML performance

Lionel Bouton wrote:
>
> Eventually when I have time to narrow down the problem myself, I'll 
> launch strace on the benchmark, study the differences and submit the 
> list of system calls to the UML coders asking why some can be faster 
> on UML than on the host kernel.
>

Ok, there's indeed something odd, but checking the trace shows that it's 
the results of the "times" system call that are odd. The actual time 
spent in the script is roughly the same when you use a stopwatch (shows 
how much I can trust my time awareness...) and the "real" time is OK, 
but the user and total time are half what I'd expect.
As the times are nearly half what they are in the host I suspect a 
simple bug like a computation based on the total system CPU time instead 
of the single core time the virtual machine is using.

So sorry no performance gains in UML :-/

Lionel