Re: [RFC] implement QUEUED spinlocks on powerpc
From: Eric Dumazet <edumazet@google.com>
Date: 2017-02-02 04:40:54
On Wed, Feb 1, 2017 at 8:04 PM, Michael Ellerman [off-list ref] wrote:
Benjamin Herrenschmidt [off-list ref] writes:quoted
On Wed, 2017-02-01 at 09:05 -0800, Eric Dumazet wrote:quoted
Hi all Is anybody working on adding QUEUED spinlocks to powerpc 64bit ? I've seen past attempts with ticket spinlocks ( https://patchwork.ozlabs.org/patch/449381/ and other related links ) But it looks ticket spinlocks are a thing of the past.Yes, we have a tentative implementation of qspinlock and pv variants: https://patchwork.ozlabs.org/patch/703139/ https://patchwork.ozlabs.org/patch/703140/ https://patchwork.ozlabs.org/patch/703141/ https://patchwork.ozlabs.org/patch/703142/ https://patchwork.ozlabs.org/patch/703143/ https://patchwork.ozlabs.org/patch/703144/ Michael, what's the status with getting that merged ?Needs a good review, and the benchmark results were not all that compelling - though perhaps they were just the wrong benchmarks.
A typical benchmark would be to use 200 concurrent netperf -t TCP_RR, through a single qdisc (protected by a spinlock) Non ticket/queued spinlocks behave quite bad in this scenario. I can try this next week if you want.