Messages in this thread | | | Date | Tue, 14 Sep 2004 21:16:37 +0200 | From | Manfred Spraul <> | Subject | Re: kernbench on 512p |
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Greg Edwards wrote:
>| > >| Which value did you use for RCU_GROUP_SIZE? I'm not sure what's the >| optimal value for 512p - probably 32 or so. > >I used what was defined in the patch > >+#define RCU_GROUP_SIZE 2 > >I can try running with a couple different values and see how it looks. > > > Ok, that explains the lockstat: I've missed data on rcu_group_state.lock.
I'd just use 32. The code uses a two-level bitmap and the group size specifies the size of the lower level. Thus you use right now a 2/256 split. Therefore you still trash the spinlock that protects the upper level. Group size 32 would generate a 32/16 split.
-- Manfred
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