From mboxrd@z Thu Jan 1 00:00:00 1970 From: Waiman Long Subject: Re: [PATCH v4 0/6] powerpc: queued spinlocks and rwlocks Date: Fri, 24 Jul 2020 17:11:36 -0400 Message-ID: References: <20200724131423.1362108-1-npiggin@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:20568 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726573AbgGXVLo (ORCPT ); Fri, 24 Jul 2020 17:11:44 -0400 In-Reply-To: <20200724131423.1362108-1-npiggin@gmail.com> Content-Language: en-US Sender: linux-arch-owner@vger.kernel.org List-ID: To: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org Cc: Will Deacon , Peter Zijlstra , Boqun Feng , Ingo Molnar , Anton Blanchard , =?UTF-8?Q?Michal_Such=c3=a1nek?= , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm-ppc@vger.kernel.org, linux-arch@vger.kernel.org On 7/24/20 9:14 AM, Nicholas Piggin wrote: > Updated with everybody's feedback (thanks all), and more performance > results. > > What I've found is I might have been measuring the worst load point for > the paravirt case, and by looking at a range of loads it's clear that > queued spinlocks are overall better even on PV, doubly so when you look > at the generally much improved worst case latencies. > > I have defaulted it to N even though I'm less concerned about the PV > numbers now, just because I think it needs more stress testing. But > it's very nicely selectable so should be low risk to include. > > All in all this is a very cool technology and great results especially > on the big systems but even on smaller ones there are nice gains. Thanks > Waiman and everyone who developed it. > > Thanks, > Nick > > Nicholas Piggin (6): > powerpc/pseries: move some PAPR paravirt functions to their own file > powerpc: move spinlock implementation to simple_spinlock > powerpc/64s: implement queued spinlocks and rwlocks > powerpc/pseries: implement paravirt qspinlocks for SPLPAR > powerpc/qspinlock: optimised atomic_try_cmpxchg_lock that adds the > lock hint > powerpc: implement smp_cond_load_relaxed > > arch/powerpc/Kconfig | 15 + > arch/powerpc/include/asm/Kbuild | 1 + > arch/powerpc/include/asm/atomic.h | 28 ++ > arch/powerpc/include/asm/barrier.h | 14 + > arch/powerpc/include/asm/paravirt.h | 87 +++++ > arch/powerpc/include/asm/qspinlock.h | 91 ++++++ > arch/powerpc/include/asm/qspinlock_paravirt.h | 7 + > arch/powerpc/include/asm/simple_spinlock.h | 288 ++++++++++++++++ > .../include/asm/simple_spinlock_types.h | 21 ++ > arch/powerpc/include/asm/spinlock.h | 308 +----------------- > arch/powerpc/include/asm/spinlock_types.h | 17 +- > arch/powerpc/lib/Makefile | 3 + > arch/powerpc/lib/locks.c | 12 +- > arch/powerpc/platforms/pseries/Kconfig | 9 +- > arch/powerpc/platforms/pseries/setup.c | 4 +- > include/asm-generic/qspinlock.h | 4 + > 16 files changed, 588 insertions(+), 321 deletions(-) > create mode 100644 arch/powerpc/include/asm/paravirt.h > create mode 100644 arch/powerpc/include/asm/qspinlock.h > create mode 100644 arch/powerpc/include/asm/qspinlock_paravirt.h > create mode 100644 arch/powerpc/include/asm/simple_spinlock.h > create mode 100644 arch/powerpc/include/asm/simple_spinlock_types.h > That patch series looks good to me. Thanks for working on this. For the series, Acked-by: Waiman Long