Re: [PATCH tip/core/rcu] Reduce overhead of cond_resched() checks for RCU

From: Dave Hansen
Date: Mon Jun 23 2014 - 20:20:39 EST


On 06/23/2014 05:15 PM, Paul E. McKenney wrote:
> Just out of curiosity, how many CPUs does your system have? 80?
> If 160, looks like something bad is happening at 80.

80 cores, 160 threads. >80 processes/threads is where we start using
the second thread on the cores. The tasks are also pinned to
hyperthread pairs, so they disturb each other, and the scheduler moves
them between threads on occasion which causes extra noise.
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