On Wed, Feb 14, 2007 at 12:14:29PM -0800, Davide Libenzi wrote:
> I think you may have mis-interpreted my words. *When* a schedule would
> block a synco execution try, then you do have a context switch. Noone
> argue that, and the code is clear. The sys_async_exec thread will block,
> and a newly woke up thread will re-emerge to sys_async_exec with a NULL
> returned to userspace. But in a "cachehit" case (no schedule happens
> during the syscall/*let execution), there is no context switch at all.
> That is the whole point of the optimization.
And I will repeat myself: that cannot be done. Tell me how the following
what if scenario works: you're in an MMX optimized memory copy and you take
a page fault. How does returning to the submittor of the async operation
get the correct MMX state restored? It doesn't.
-ben
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