Re: NR_TASKS=4096

Ingo Molnar (
Tue, 22 Apr 1997 12:05:02 +0200 (MET DST)

On Tue, 22 Apr 1997, Dean Gaudet wrote:

> Should I run into problems with NR_TASKS above 1024? I got a locked
> system at 4096, it locks right after decompressing the kernel before it
> does anything else. This is a ppro and 2.0.30. It's running fine now at
> 1024 now, but it needs far more (lots of light weight 80k processes).

hm, with NR_TASKS 4096 i think you get a BIG tasks[] array (2Megs). If you
make static arrays too big i think the default uncompressor gets into
trouble ... have you tried 'make bzImage'?

another problem: the default GDT setup is _just_ too small for 4096. The
GDT is limited to 64KB, and Linux needs 2 descriptors per task. Thats
4096, but Linux also needs 8 special descriptors. So, does it work with
NR_TASKS 4000? [i'm not aware of any limitation that says that NR_TASKS
should be a power of two ... but i could be wrong]. 2048 should work

do you need _much_ more than 4000 tasks [threads]? If yes then it's time
to think about soft-switching descriptors.

-- mingo