Am 12.05.2011 06:33, schrieb Jonathan M Davis: > On 2011-05-11 21:14, dsimcha wrote: >> I'm thinking about ways to remove the global lock from the garbage >> collector for most small allocations. I'm basically thinking of making >> the free lists thread local. Every scheme I can come up with that >> doesn't require a radical overhaul of the current implementation >> requires every thread having a unique ID. I want to do this as simply >> and efficiently as possible, preferably using dense integers. Is it >> reasonable to assume that no program will ever need more than 2 ^^ 16 >> thread (about 65,000) simultaneously so that I can store these indices >> as ushorts? If a program creates a lot of short-lived threads, the >> indices will be recycled, so having a huge number of threads >> non-simultaneously is not a problem. > > I don't think that you can legally create that many threads on a typical OS. > I'd have to check, but as I recall, the typical limit is much lower than that > - still in the tens of thousands, I think, but not that high. > > - Jonathan M Davis
On Windows you get a DWORD (32bit int AFAIK) from GetCurrentThreadId(), so that seems to be a technical limit there. On Linux there's pthread_t which seems to be a 32bit uint on x86 and 64bit ulong on amd64. However, see: http://stackoverflow.com/questions/344203/maximum-number-of-threads-per-process-in-linux It seems like it's limited by the available stack space (especially on 32bit systems) Similar on Windows: http://blogs.msdn.com/b/oldnewthing/archive/2005/07/29/444912.aspx Cheers, - Daniel
