secret of light-weight user thread
Kazu Yamamoto ( 山本和彦 )
kazu at iij.ad.jp
Wed Sep 7 09:13:09 CEST 2011
Thank you for explanation.
> - We have an accurate GC, which means that the Haskell stack can be
> movable, whereas the C stack isn't. So we can start with small
> stacks and enlarge them as necessary.
What is the difference between the Haskell stack and the C stack?
I guess that the C stack means CPU's stack. Is the Haskell stack a
virtual stack for a virtual machine (STG machine or something)?
I quickly read several papers but I have no idea.
> - We only preempt threads at safe points. This means that the
> context we have to save at a context switch is platform-independent
> and typically much smaller than the entire CPU context. Safe
> points are currently on allocation, which is frequent enough in GHC
> for this to be indistinguishable (most of the time) from true
I seems to me that StgRun saves CPU registers. You mean that StgRun
depends on CPU a bit but the rest part of context is CPU independent?
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