virtualbox.org

My thoughts on MutiCores, MultiCPUs, Hyperthreading, Benchmarks etc. etc. (who cares what I think?)

I'm with Martin as far as using threads goes.

I only own single CPU hosts, all of which support Hyperthreading, two of which only have 2 cores/4 threads. The other 4 have 4 cores/8 threads. In my experience with guests on various platforms running various guests, setting all threads to a guest does nothing but slow everything down. Both VirtualBox and VMWare warn users not to assign all threads to a guest. I think they must have reasons.

There are so many factors that can affect performance, the hardware, the OS, the software etc. For example if a software program is not optimized for multicore/hyperthreading, it's not going to run as well as software that is. I don't compile anything but my understanding is it's a sequential process so unless one has a compiler that can break up the sections of code and run each on separate CPUs/threads I don't see much of an advantage. I seem to remember reading articles that say hyperthreading has no advantage, a 15% increase in performance, or a slowdown in performance.

All results seem rather anecdotal and tied to specific CPUs , hardware and software.

The bottom line is I think, run what works best for the job. The settings may have to be changed depending on the job or, just use what gives the best overall performance.

I'm never talking about this again.

FWIW, computer "geeks" are as bad as "audiophiles" if not worse. IMO.

Hi Socratis,
Hi Martin,
Hi LouKingJr,

First of all, thank you for all your efforts in trying to solve this problem.

Weirdly enough, I also have installed VMWare and Paralells Desktop on this Mac Pro that I flashed.
And I've set-up a build environment for both of them into Debian 8.2 using the exact same disk image and the exact same software packages.
All of them (Parallels Desktop, VMWare and VB 4.3.34) are set to use up to 16 cores.
And they ALL do use the 16 cores to 100% of each core (or thread) even though the process is MUCH faster when using VMWare or PD than when using VB 4.3.34 (48 minutes for both PD and VMWare ; 62 for VB 4.3.34...).

Only exception : VB 5.0.10.
I do see NO reason why 5.0.10 would think my hardware is different than it is... and other Virtualization programs do not.
Of course, mentioning that I did flash it to be considered as the same computer, but from the new generation, I knew that this would be used as an argument to explain the unexplainable.

As I said : my concern in the first place is not performance, but convenience and ease of use.

But it seems VB does not fit my needs, as this is used to allow people of the team working on that custom ROM to build remotely onto my machine (over the day, I do not use the host as I am not at home... thus they can use it to make more rapid progress on their development).
So what I need is a VM that will allow for the fastest build possible with the best ease of use.
It seems I will have to use paid software to have that.
So be it...

I'll give VB a look from time to time to see how it's evolving... but for now, I will leave as it is working super good, but does not fit my needs.

And loukingjr : I am an audiophile, but not a geek.
So I will not talk about it anymore.
I think we will differ on that...

NexusPenguin wrote:Hi LouKingJr,
…
And loukingjr : I am an audiophile, but not a geek.
So I will not talk about it anymore.
I think we will differ on that...

I enclosed audiophiles and geeks in quotes for a reason.

Hi LouKingJR,

LOL... yes I noticed.
And maybe I misunderstood when I assumed that you consider them both poorly

Well, they are of the same species I guess.
But it's a species I like... more or less
To be honest, I think I am more a "melomane" than an 'audiophile"...

And so we agree

Regards.

FRED

Actually I think of "audiophiles" poorly, audiophiles are fine.

edit: I neglected to add, a mélomane is a very good thing.