On Aug 27 21:42, Ken Brown via Cygwin wrote: > On 8/27/2020 8:17 AM, Kristian Ivarsson via Cygwin wrote: > > Hi Corinna > > > > > > Dear cygwin folks > > > > > > > > It seems like there's a limit of the number of possible child > > > > processes defined to 256 with 'NPROCS' in //winsup/cygwin/child_info.h > > > > used in 'cprocs' in //winsup/cygwin/sigproc.cc > > > > > > > > 256 is quite few possible children in an enterprise environment and > > > > perhaps the limit should be limited by the physical resources or > > > possibly Windows ? > > > > > > The info has to be kept available in the process itself so we need this > > > array of NPROCS * sizeof (pinfo). > > > > > > Of course, there's no reason to use a static array, the code could just as > > > well use a dynamically allocated array or a linked list. It's just not > > > the way it is right now and would need a patch or rewrite. > > > > > > As for the static array, sizeof pinfo is 64, so the current size of the > > > array is just 16K. We could easily bump it to 64K with NPROCS raised to > > > 1024 for the next Cygwin release, at least on 64 bit. > > > I don't think we should raise this limit for 32 bit Cygwin, which is kind > > > of EOL anyway, given the massive restrictions. > > > > I don't know the exact purpose of this and how the cprocs is used, but I'd > > prefer something totally dynamic 7 days out of 7 or otherwise another limit > > would just bite you in the ass some other day instead ;-) > > > > A linked list could be used if you wanna optimize (dynamic) memory usage but > > an (amortized) array would probably provide faster linear search but I guess > > simplicity of the code and external functionality is the most important > > demands for this choice > > Any change here (aside from just increasing NPROCS) would have to be done > with care to avoid a performance hit. I looked at the history of changes to > sigproc.cc, and I found commit 4ce15a49 in 2001 in which a static array > something like cprocs was replaced by a dynamically allocated buffer in > order to save DLL space. This was reverted 3 days later (commit e2ea684e) > because of performance issues.
Yup, that's one of the problems to keep in mind. Corinna -- Corinna Vinschen Cygwin Maintainer -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
