Re: [Boost-cmake] Labels for known failures

Subject: Re: [Boost-cmake] Labels for known failures
From: David Cole (david.cole_at_[hidden])
Date: 2009-05-19 09:46:36

On Tue, May 19, 2009 at 9:30 AM, Michael Jackson <
mike.jackson_at_[hidden]> wrote:

> I am having some trouble wrapping my head around what exactly is meant by:
>
> GetLogicalProcessorsPerPhysical
>
> Is that logical per core, per CPU or what? Right now I calculate the value
> based on the number of logical and physical. So for my Xeon with
> HyperThreading I get a value of 8. Does that seem correct?

It seems correct to me. I'm not sure (maybe nobody is, or if somebody is,
maybe he'll chime in...?) what we mean by logical and physical processors
anyway. I suppose what is meant in theory is that a physical processor can
run independently of all the other physical processors whereas logical ones
might need to share physical resources and therefore not be as accurate a
measure of what performance can be achieved on a machine...?

Perhaps just simple "number of cpus" and "number of cores" measurements
would be better to record.

If you have a "number of logical" and "number of physical" measurements,
then LogicalPerPhysical should just be the simple derived quantity "log /
phys" (Why do we bother to record something so simply computable from other
measurements...?) -- so I think the value you are currently calculating is
correct.

> ......
> Also, there is another entry:
> Is64Bits: 0
>
> Which can mean multiple things. The way it is written now this simply tells
> if CMake was compiled in 32Bit or 64 Bit mode. Was that supposed to mean is
> the CPU 64 Bit capable?

I would interpret the meaning of Is64Bits as "is the OS capable of running
64-bit applications?" -- remember these are all measurements about the
computer on which a dashboard is running. If it was a measurement about
CMake's build type, I would expect it to be named CMakeIs64Bit (or something
similar)...

HTH,
David