From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4AC34C433DF for ; Fri, 24 Jul 2020 21:11:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F0702070B for ; Fri, 24 Jul 2020 21:11:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="cil1XNPV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726736AbgGXVLp (ORCPT ); Fri, 24 Jul 2020 17:11:45 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:24782 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726411AbgGXVLo (ORCPT ); Fri, 24 Jul 2020 17:11:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595625103; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tgk0E/B+fKLI4HapciZOOHShfeB4adj+yNndqo5HAqc=; b=cil1XNPVb6qCS5eOC9TwJy+Zs2IXvFYnt8Gqhy2WKEgPbZU/gksB1Ouv4h7RfEsoB/++iQ E0z9/zUjsWsrXdXpxvVAfISeMK5oYIjOeoE8uYSz7r/ia8Z7Zazlvn7vdXz102qx05xbhH Y301+MqJmUSb7kpLKOlh3iOiRdsRYwg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-467-EvQuSqI9Np-gVoJuVaSCpw-1; Fri, 24 Jul 2020 17:11:41 -0400 X-MC-Unique: EvQuSqI9Np-gVoJuVaSCpw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6ED61106B251; Fri, 24 Jul 2020 21:11:39 +0000 (UTC) Received: from llong.remote.csb (ovpn-117-203.rdu2.redhat.com [10.10.117.203]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9267410013C2; Fri, 24 Jul 2020 21:11:36 +0000 (UTC) Subject: Re: [PATCH v4 0/6] powerpc: queued spinlocks and rwlocks 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 References: <20200724131423.1362108-1-npiggin@gmail.com> From: Waiman Long Organization: Red Hat Message-ID: Date: Fri, 24 Jul 2020 17:11:36 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200724131423.1362108-1-npiggin@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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