[Insight-developers] Visual Studio 2012+ Parallelism

[Bradley Lowekamp]

Matt,

My point was that with VS10 and prior we were getting good target level parallelism, while it appears that with VS11 we are no long getting good target level parallelism and need this additional compiler level parallelism that "/MP" provides.

I don't understand is something change to cause this. Why?

Have other experience the same things?

Brad

On Feb 10, 2014, at 10:53 AM, Matt McCormick <matt.mccormick at kitware.com> wrote:

> Hi Brad,
> 
> My understanding is that this flag can be very helpful for speeding
> things up when the system can handle it, but it is not on by default,
> because, from the article "The downside is that the IDE will still
> perform target level parallelism along with object level parallelism
> which can lead to excessive parallelism grinding your machine and GUI
> to a halt."
> 
> Thanks,
> Matt
> 
> On Mon, Feb 10, 2014 at 9:30 AM, Bradley Lowekamp
> <blowekamp at mail.nih.gov> wrote:
>> Hello,
>> 
>> I just added the "/MP" flag to my "Win32-VS11-Release-Shared"[1] build, based on information from reading Kitware blog entry entitled "CMake: building with all your cores"[3]. Adding this flag changed the build time from 5h47min to 1hr10min . I don't recall having to do this before with VS10, VS9, has something changed with these more recent Visual Studios?
>> 
>> The system is running on a VM, allocated 4 cores and 16GB of memory. Many of the VS11/VS12 build have been taking over 2hrs and a couple much longer.
>> 
>> This chart is an indication of the excessive build time on this system:
>> http://open.cdash.org/viewSite.php?siteid=8833&project=2&currenttime=1391907600
>> 
>> Incidentally the recent VS11 builds I have setup for SimpleITK don't seem to suffer from the same issue.
>> 
>> 
>> 
>> [1] http://open.cdash.org/buildSummary.php?buildid=3213955
>> [2] http://open.cdash.org/viewNotes.php?buildid=3213955
>> [3] http://www.kitware.com/blog/home/post/434
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