Re: [PATCH, RFC] v7 scalable classic RCU implementation
From: Manfred Spraul
Date: Mon Oct 27 2008 - 15:46:11 EST
Paul E. McKenney wrote:
Agreed. Perhaps a good change to make while introducing stall detection
to preemptable RCU -- there would then be three examples, which should
allow good generalization.
Two implementations. IMHO the current rcu-classic code should be dropped
immediately when you add rcu-tree:
rcu-classic is buggy, as far as I can see long-running interrupts on
nohz cpus are not handled correctly. I don't think it makes sense to
keep it in the kernel in parallel to rcu-tree.
I would propose that rcu-tree replaces rcu-classic.
I'll continue to update rcu-state, I think that it will achieve lower
latency than rcu-tree [average/max time between call_rcu() and
destruction callback] and it doesn't have the irq disabled loop to find
the missing cpus.
If I find decent benchmarks where I can quantify the advantages, then
I'll propose to merge rcu-state as a third implementation in addition to
rcu-tree and rcu-preempt.
Paul: What do you think?
--
Manfred
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