[Haskell-cafe] [Rejected Paper] Experience Report: Writing NetBSD Sound Drivers in Haskell

John Meacham john at repetae.net
Tue Jun 10 11:49:19 UTC 2014

Hmm... if we allocate the gc_stack on an aligned boundry, can we
recover the arena by keeping a pointer at its base? sort of like I
recover the cache block pointer from an arbitrary heap location by
rounding down to the block boundry.

The main issue would be how it affects allocation speed, its okay to
make the GC slower as long as allocation is still fast, Before
pre-populating the cache pointers sped things up considerably, how
would it make sure to use one from the current arena without slowing
down allocation in general?


On Tue, Jun 10, 2014 at 4:42 AM, Kiwamu Okabe <kiwamu at debian.or.jp> wrote:
> Hi John,
> On Tue, Jun 10, 2014 at 8:28 PM, John Meacham <john at repetae.net> wrote:
>> Ah. I think I see what you mean by reentrant in your paper. Can you
>> point me to your context switching code in ajhc?
> Here is.
> https://github.com/ajhc/ajhc/blob/arafura/rts/rts/conc.c#L33
> It's a sample with pthread.
> But CLHs can choose any thread style with calling C code that generate
> context switch.
>> Is SMP a concern for you or are you mainly concerned about hardware interrupts?
> Both thread on SMP and interrupt.
> Former uses active context switch, and the example is the above.
> Later uses passive context switch, however the interrupt context
> begins on C context.
> The C context create new "arena" when calling C => Haskell.
> Thank's,
> --
> Kiwamu Okabe at METASEPI DESIGN

John Meacham - http://notanumber.net/

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