Messages in this thread | | | Date | Fri, 10 Dec 1999 00:34:50 +0100 (CET) | From | Ingo Molnar <> | Subject | Re: Per-Processor Data Paget |
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On Thu, 9 Dec 1999, Scott Lurndal wrote:
> > it's not even possible - think about threads on different processors > > running at once. Which fixed address? Page tables are shared.
> It certainly can be done, and it has been done. > > Only the page table containing the virt addr 0xc0000000 need be > different between multiple threads. > > Page tables don't _have_ to be shared, either, they could, > instead be duplicated. > > In this proposal, however, only the page directory need be > different, the page tables for all user virtual address pages > can be shared between threads which shared address spaces.
clone()ing costs go up immediately, from the current 10 usecs cost to create a process to 50-100 usecs, plus MM handling gets more complicated. Plus in PAE mode this would be even more complicated (because two levels need to be private to the thread). I dont think this brings any good.
what you propose is not possible without destroying true threads.
-- mingo
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