Thin Lock Implementation

[Jb]

"Steven Schveighoffer" <schveiguy at yahoo.com> wrote in message 
news:g8emvj$1cu5$1 at digitalmars.com...
> "Sascha Katzner" wrote
>> Steven Schveighoffer wrote:
>>> On a 32-bit system, the amount of addressable memory space and the
>>> stack size are the factors that limit the number of threads.  For
>>> example, if addressable space is 2GB, and each thread has a 1MB
>>> stack, that's 2000 threads max (this is the typical situation for
>>> Windows).
>>
>> Not exactly right, since the stack is organized in 4kb pages and these
>> pages are not initialized until they are first used they usually require
>> a lot less than 1mb.
>
> Hm... I read the limit above online 
> (http://blogs.msdn.com/oldnewthing/archive/2005/07/29/444912.aspx).  I 
> think maybe the pages aren't initialized, but doesn't the system have to 
> reserve them because it has to guarantee a 1MB stack for each?  Or maybe 
> that guy is completely wrong, or the concept has been fixed :)

Read the whole page ;-)

The 1MB is just the default stack size if you pass a value of zero to the 
CreateThread function, and usualy most linkers / librarys whatever do that.

You can override this by specifying the stack size. And as he said he could 
then create 13000 rather than 2000 threads.

But the actualy mimimum size is 64k, as that is the granularity of the 
windows allocator. You can check by calling getSystemInfo, and examining the 
allocationGranularity, but I've never seen it return anything other than 
64k.