[vtk-developers] Multithreading with Win32 threads

Tue Jan 25 14:11:29 EST 2011

I am going to change it to 1024 unless someone objects for the immediate
term. And then from there switch it to be dynamic and deprecate
VTK_MAX_THREAD entirely.

On Tue, Jan 25, 2011 at 8:27 AM, David Partyka <david.partyka at kitware.com>wrote:

> I definitely agree but this looks like it should be given
> a deprecation cycle as it involves removing API, there are set/get macros
> and VTK_MAX_THREAD is a const in a global header. Though, nearly all of the
> usage of VTK_MAX_THREAD is in vtkMultiThreader and it definitely would not
> be hard to switch it to dynamically store threads.
>
> That said, I can check in a much larger value for VTK_MAX_THREAD right now.
> How about 128? 256? 1024? INT_MAX?
>
> After that, myself or someone else can switch it to use a vector instead of
> a fixed size array and then add the deprecation macros so people know it's
> going away. Does this sound reasonable? Or too cautious? :-p
>
>
> On Tue, Jan 25, 2011 at 8:04 AM, Will Schroeder <
> will.schroeder at kitware.com> wrote:
>
>> I agree with Ken, IMO we should remove hardcoded limits on threads. In
>> fact I can see creating some specialized code to determine the "optimal"
>> number of threads (with provisions for manual override). After all in the
>> Nat'l Lab world that Ken/Sandia resides in, I've heard the dudes talk about
>> hundreds or thousands of processes, etc....it's evolving fast and we don't
>> want to have to keep changing this.
>>
>> W
>>
>>
>>
>> On Mon, Jan 24, 2011 at 11:14 AM, Moreland, Kenneth <kmorel at sandia.gov>wrote:
>>
>>>  Why is there a hardcoded maximum in the first place?  It seems to me
>>> that whatever number you choose now will be excessively high and/or obsolete
>>> in the coming years as the number of cores per processor grows.
>>>
>>> -Ken
>>>
>>>
>>>
>>> On 1/24/11 8:04 AM, "Bill Lorensen" <bill.lorensen at gmail.com> wrote:
>>>
>>> ITK has had the max set to 128 for quite a while.
>>>
>>> On Mon, Jan 24, 2011 at 9:53 AM, David Partyka
>>> <david.partyka at kitware.com> wrote:
>>> > Sure thing, especially considering one can get a machine with dual
>>> > Hexa-cores + Hyper Threading resulting in 24 available cores.
>>> >
>>> > On Mon, Jan 24, 2011 at 9:39 AM, David Cole <david.cole at kitware.com>
>>> wrote:
>>> >>
>>> >> I think it's just old and leftover, and nobody has yet found a
>>> compelling
>>> >> need for more than 8 threads on Windows. It should be fine to increase
>>> this
>>> >> number, especially if you actually have a Windows box with more than 8
>>> >> processors on it.
>>> >>
>>> >> Feel free to change your build locally to increase that value. Perhaps
>>> >> somebody here on the VTK developers list is also contemplating more
>>> powerful
>>> >> Window machines these days... Anybody here want to bump this up and
>>> commit
>>> >> the change?
>>> >>
>>> >>
>>> >> On Mon, Jan 24, 2011 at 5:11 AM, Pavel Pokutnev
>>> >> <pavel.pokutnev at googlemail.com> wrote:
>>> >>>
>>> >>> Hello vtk-devs,
>>> >>>
>>> >>> sorry, but I would like to repeat my question.
>>> >>> There is a define VTK_MAX_THREADS in "Common/vtkSystemIncludes.h". It
>>> >>> is defined to 8 for Win32 threads, but for all other platforms to 32.
>>> >>> What is the cause for this non-conformity?
>>> >>>
>>> >>> Best regards,
>>> >>> Pavel
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>>> >>
>>> >
>>> >
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>>>
>>>    ****      Kenneth Moreland
>>>     ***      Sandia National Laboratories
>>> ***********
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>>
>>
>> --
>> William J. Schroeder, PhD
>> Kitware, Inc.
>> 28 Corporate Drive
>> Clifton Park, NY 12065
>> will.schroeder at kitware.com
>> http://www.kitware.com
>> (518) 881-4902
>>
>
>
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