From patchwork Wed Aug 2 16:46:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guo Ren X-Patchwork-Id: 13338529 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3A66C41513 for ; Wed, 2 Aug 2023 16:49:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231669AbjHBQtZ (ORCPT ); Wed, 2 Aug 2023 12:49:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232271AbjHBQtF (ORCPT ); Wed, 2 Aug 2023 12:49:05 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07C912D78; Wed, 2 Aug 2023 09:48:46 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9A51C61A3C; Wed, 2 Aug 2023 16:48:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 07D8BC433CA; Wed, 2 Aug 2023 16:48:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690994925; bh=XpJMmQpizgl+1q4faLgZyV4Sr5SWoDQzo87jc2k0hEU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Rgxujrsdn7f+bcZFJbQ7fNjqz5y2CrBgF0JiPl0DEbMPu20EiePiHkH95Lmot58DW LviM3KysginZdajdwkNuvDoxVNN9RrLMOjPSuZ2jRVFlm0Qny2n4KMliWznJBLtDdM PysXqLOrB6cwwXJ7jKWDbYVbH0jnEiJgiskSOUOEj3Oeoj/ZstrC+OQYehdAcghRJK G7L0DezO+mrmdTlz+SbrU0xEuUAXSYjh3wFuhnVhocrtahkE+ip2vFt+KKjTcY8dze FrXIL/40ohIWf2ObIM0DmN2LJ5i1atvvrNMdz0WAJ+g3S86+2/6kXwSMt708WfOkjC iMkIyJYOTzcAA== From: guoren@kernel.org To: paul.walmsley@sifive.com, anup@brainfault.org, peterz@infradead.org, mingo@redhat.com, will@kernel.org, palmer@rivosinc.com, longman@redhat.com, boqun.feng@gmail.com, tglx@linutronix.de, paulmck@kernel.org, rostedt@goodmis.org, rdunlap@infradead.org, catalin.marinas@arm.com, conor.dooley@microchip.com, xiaoguang.xing@sophgo.com, bjorn@rivosinc.com, alexghiti@rivosinc.com, keescook@chromium.org, greentime.hu@sifive.com, ajones@ventanamicro.com, jszhang@kernel.org, wefu@redhat.com, wuwei2016@iscas.ac.cn Cc: linux-arch@vger.kernel.org, linux-riscv@lists.infradead.org, linux-doc@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-csky@vger.kernel.org, Guo Ren , Guo Ren Subject: [PATCH V10 04/19] riscv: qspinlock: Add basic queued_spinlock support Date: Wed, 2 Aug 2023 12:46:46 -0400 Message-Id: <20230802164701.192791-5-guoren@kernel.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20230802164701.192791-1-guoren@kernel.org> References: <20230802164701.192791-1-guoren@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Guo Ren The requirements of qspinlock have been documented by commit: a8ad07e5240c ("asm-generic: qspinlock: Indicate the use of mixed-size atomics"). Although RISC-V ISA gives out a weaker forward guarantee LR/SC, which doesn't satisfy the requirements of qspinlock above, it won't prevent some riscv vendors from implementing a strong fwd guarantee LR/SC in microarchitecture to match xchg_tail requirement. T-HEAD C9xx processor is the one. We've tested the patch on SOPHGO sg2042 & th1520 and passed the stress test on Fedora & Ubuntu & OpenEuler ... Here is the performance comparison between qspinlock and ticket_lock on sg2042 (64 cores): sysbench test=threads threads=32 yields=100 lock=8 (+13.8%): queued_spinlock 0.5109/0.00 ticket_spinlock 0.5814/0.00 perf futex/hash (+6.7%): queued_spinlock 1444393 operations/sec (+- 0.09%) ticket_spinlock 1353215 operations/sec (+- 0.15%) perf futex/wake-parallel (+8.6%): queued_spinlock (waking 1/64 threads) in 0.0253 ms (+-2.90%) ticket_spinlock (waking 1/64 threads) in 0.0275 ms (+-3.12%) perf futex/requeue (+4.2%): queued_spinlock Requeued 64 of 64 threads in 0.0785 ms (+-0.55%) ticket_spinlock Requeued 64 of 64 threads in 0.0818 ms (+-4.12%) System Benchmarks (+6.4%) queued_spinlock: System Benchmarks Index Values BASELINE RESULT INDEX Dhrystone 2 using register variables 116700.0 628613745.4 53865.8 Double-Precision Whetstone 55.0 182422.8 33167.8 Execl Throughput 43.0 13116.6 3050.4 File Copy 1024 bufsize 2000 maxblocks 3960.0 7762306.2 19601.8 File Copy 256 bufsize 500 maxblocks 1655.0 3417556.8 20649.9 File Copy 4096 bufsize 8000 maxblocks 5800.0 7427995.7 12806.9 Pipe Throughput 12440.0 23058600.5 18535.9 Pipe-based Context Switching 4000.0 2835617.7 7089.0 Process Creation 126.0 12537.3 995.0 Shell Scripts (1 concurrent) 42.4 57057.4 13456.9 Shell Scripts (8 concurrent) 6.0 7367.1 12278.5 System Call Overhead 15000.0 33308301.3 22205.5 ======== System Benchmarks Index Score 12426.1 ticket_spinlock: System Benchmarks Index Values BASELINE RESULT INDEX Dhrystone 2 using register variables 116700.0 626541701.9 53688.2 Double-Precision Whetstone 55.0 181921.0 33076.5 Execl Throughput 43.0 12625.1 2936.1 File Copy 1024 bufsize 2000 maxblocks 3960.0 6553792.9 16550.0 File Copy 256 bufsize 500 maxblocks 1655.0 3189231.6 19270.3 File Copy 4096 bufsize 8000 maxblocks 5800.0 7221277.0 12450.5 Pipe Throughput 12440.0 20594018.7 16554.7 Pipe-based Context Switching 4000.0 2571117.7 6427.8 Process Creation 126.0 10798.4 857.0 Shell Scripts (1 concurrent) 42.4 57227.5 13497.1 Shell Scripts (8 concurrent) 6.0 7329.2 12215.3 System Call Overhead 15000.0 30766778.4 20511.2 ======== System Benchmarks Index Score 11670.7 The qspinlock has a significant improvement on SOPHGO SG2042 64 cores platform than the ticket_lock. Signed-off-by: Guo Ren Signed-off-by: Guo Ren --- arch/riscv/Kconfig | 16 ++++++++++++++++ arch/riscv/include/asm/Kbuild | 3 ++- arch/riscv/include/asm/cmpxchg.h | 24 ++++++++++++++++++++++++ arch/riscv/include/asm/spinlock.h | 17 +++++++++++++++++ 4 files changed, 59 insertions(+), 1 deletion(-) create mode 100644 arch/riscv/include/asm/spinlock.h diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 93ff677d2be5..e89a3bea3dc1 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -438,6 +438,22 @@ config NODES_SHIFT Specify the maximum number of NUMA Nodes available on the target system. Increases memory reserved to accommodate various tables. +choice + prompt "RISC-V spinlock type" + default RISCV_TICKET_SPINLOCKS + +config RISCV_TICKET_SPINLOCKS + bool "Using ticket spinlock" + +config RISCV_QUEUED_SPINLOCKS + bool "Using queued spinlock" + depends on SMP && MMU + select ARCH_USE_QUEUED_SPINLOCKS + help + Make sure your micro arch LL/SC has a strong forward progress guarantee. + Otherwise, stay at ticket-lock. +endchoice + config RISCV_ALTERNATIVE bool depends on !XIP_KERNEL diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild index 504f8b7e72d4..a0dc85e4a754 100644 --- a/arch/riscv/include/asm/Kbuild +++ b/arch/riscv/include/asm/Kbuild @@ -2,10 +2,11 @@ generic-y += early_ioremap.h generic-y += flat.h generic-y += kvm_para.h +generic-y += mcs_spinlock.h generic-y += parport.h -generic-y += spinlock.h generic-y += spinlock_types.h generic-y += qrwlock.h generic-y += qrwlock_types.h +generic-y += qspinlock.h generic-y += user.h generic-y += vmlinux.lds.h diff --git a/arch/riscv/include/asm/cmpxchg.h b/arch/riscv/include/asm/cmpxchg.h index 2f4726d3cfcc..d12231d752a4 100644 --- a/arch/riscv/include/asm/cmpxchg.h +++ b/arch/riscv/include/asm/cmpxchg.h @@ -11,12 +11,36 @@ #include #include +static inline ulong __xchg16_relaxed(ulong new, void *ptr) +{ + ulong ret, tmp; + ulong shif = ((ulong)ptr & 2) ? 16 : 0; + ulong mask = 0xffff << shif; + ulong *__ptr = (ulong *)((ulong)ptr & ~2); + + __asm__ __volatile__ ( + "0: lr.w %0, %2\n" + " and %1, %0, %z3\n" + " or %1, %1, %z4\n" + " sc.w %1, %1, %2\n" + " bnez %1, 0b\n" + : "=&r" (ret), "=&r" (tmp), "+A" (*__ptr) + : "rJ" (~mask), "rJ" (new << shif) + : "memory"); + + return (ulong)((ret & mask) >> shif); +} + #define __xchg_relaxed(ptr, new, size) \ ({ \ __typeof__(ptr) __ptr = (ptr); \ __typeof__(new) __new = (new); \ __typeof__(*(ptr)) __ret; \ switch (size) { \ + case 2: \ + __ret = (__typeof__(*(ptr))) \ + __xchg16_relaxed((ulong)__new, __ptr); \ + break; \ case 4: \ __asm__ __volatile__ ( \ " amoswap.w %0, %2, %1\n" \ diff --git a/arch/riscv/include/asm/spinlock.h b/arch/riscv/include/asm/spinlock.h new file mode 100644 index 000000000000..c644a92d4548 --- /dev/null +++ b/arch/riscv/include/asm/spinlock.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __ASM_RISCV_SPINLOCK_H +#define __ASM_RISCV_SPINLOCK_H + +#ifdef CONFIG_QUEUED_SPINLOCKS +#define _Q_PENDING_LOOPS (1 << 9) +#endif + +#ifdef CONFIG_QUEUED_SPINLOCKS +#include +#include +#else +#include +#endif + +#endif /* __ASM_RISCV_SPINLOCK_H */