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Wed, 13 Sep 2023 13:28:53 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEosvqU1OmLV+VJSPzBQB9wJjlW4Hu8XnlJnqgJRY8LGsur+q00iHnUVagueksTtX/wtOrk+g== X-Received: by 2002:a05:6870:d58e:b0:1a6:cfcc:befd with SMTP id u14-20020a056870d58e00b001a6cfccbefdmr2460120oao.5.1694636932964; Wed, 13 Sep 2023 13:28:52 -0700 (PDT) Received: from redhat.com ([2804:1b3:a803:4ff9:7c29:fe41:6aa7:43df]) by smtp.gmail.com with ESMTPSA id ee23-20020a056870c81700b001cd20f30898sm52574oab.24.2023.09.13.13.28.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 13 Sep 2023 13:28:52 -0700 (PDT) Date: Wed, 13 Sep 2023 17:28:42 -0300 From: Leonardo Bras To: guoren@kernel.org Cc: 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, 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 Subject: Re: [PATCH V11 05/17] riscv: qspinlock: Add basic queued_spinlock support Message-ID: References: <20230910082911.3378782-1-guoren@kernel.org> <20230910082911.3378782-6-guoren@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230910082911.3378782-6-guoren@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-csky@vger.kernel.org On Sun, Sep 10, 2023 at 04:28:59AM -0400, guoren@kernel.org wrote: > 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/spinlock.h | 17 +++++++++++++++++ > 3 files changed, 35 insertions(+), 1 deletion(-) > create mode 100644 arch/riscv/include/asm/spinlock.h > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index 2c346fe169c1..7f39bfc75744 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -471,6 +471,22 @@ 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 IIUC here you take the asm-generic/spinlock.h (which defines arch_spin_*()) and include the asm-generic headers of mcs_spinlock and qspinlock. In this case, the qspinlock.h will provide the arch_spin_*() interfaces, which seems the oposite of the above description (ticket spinlocks being the standard). Shouldn't ticket-spinlock.h also get included here? (Also, I am probably missing something, as I dont' see the use of mcs_spinlock here.) > 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/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 Any reason the above define couldn't be merged on the ifdef below? > + > +#ifdef CONFIG_QUEUED_SPINLOCKS > +#include > +#include > +#else > +#include > +#endif > + > +#endif /* __ASM_RISCV_SPINLOCK_H */ > -- > 2.36.1 > Thanks! Leo