In article <38B94CE3.D4ADA16@ping.at> you wrote:
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> This patch adds two functions (down_spin and down_adapt) that try
> to address the problems of
> - semaphores that are generally held for a very short time, so
> scheduling on contention is very inefficient in most cases,
> but still necessary in some others (to avoid deadlocks)
> - spinlocks that are occasionally held for a long time, so scheduling
> would be efficient in some cases - but that have sometimes to be
> taken where scheduling simply is not allowed.
Nice idea! One more thought: Would it be possible (and useful) if the time
spent in spinning is changed dynamically?
I mean:
1) If a lock needed schedule the previous time, decrease the time
spinning for the next time the lock is contented
2) If a lock didn't need to schedule, have a little more patience
and spin somewhat longer the next time
The heuristic can look a bit like the read-ahead in the vfs....
Greetings,
Arjan van de Ven
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