Re: [PATCH 3/3] High-res-timers part 3 (posix to hrposix) take 20

From: William Lee Irwin III (
Date: Mon Dec 09 2002 - 21:11:07 EST

William Lee Irwin III wrote:
>> My original allocator(s) used a radix tree structured bitmap like this
>> in order to provide hard constant time bounds, but statically-allocated
>> them. Static allocation didn't fit in with larger pid space, though.

On Mon, Dec 09, 2002 at 08:55:47PM -0500, Jim Houston wrote:
> Gee Bill, what can I say? I'm sorry I misattributed your work to Ingo.

Ingo did a large bit of work wrt. mergeability, the for_each_task_pid()
macro, folded the separately allocated idtag structures into the task_t,
redid the pid allocator to handle thelarger spaces, and fixed several
severe bugs, so he should be given due credit. I'd say it was a
collaborative effort, though separated somewhat by the times we
actually worked on it.

On Mon, Dec 09, 2002 at 08:55:47PM -0500, Jim Houston wrote:
> I'm curious about the reaction to recursion. I use the obvious loop
> for the lookup path, but the allocate and remove cases start getting
> ugly as an iterative solution.

Deep call stacks are not cheap on all arches, ISTR SPARC(64?) and S/390
having some relatively obscene overheads. Going iterative didn't
actually look that bad here, but sleeping etc. for memory weren't in
the picture for me.

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