From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 254FB6EB55 for ; Thu, 25 Jan 2024 15:11:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706195517; cv=none; b=WhqFdIu4mS/W1SZI+XjVuVucDY9TxPFU7L2inqw+c7Oh3MbRCnYtyBHmWujjLfxgoE/i0LeLuaKCsPC+BXDxbe2wacqJNvFqA/iA3VomO7fPX8nd9ZRLTObio9fWlWan0hx3zRYXUeJeNBx6qZHlN9/zsp1nj3Jxmgk4y4U8CiA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706195517; c=relaxed/simple; bh=qqT5s5v8kHRYnSn/7vdNCIRU1OWwV2sCCtz6w1JM1Uc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=RosvTBAcgjTlCIWnr+Y7esN83kbQnidY2mpsiGg11ZRxXfenK8Ik4A8z4xOXhp8MW/ApjZFszC5xJzO9OpoU8A75Y5oyM+qG8SK5OK7vMTlaM7aDEoTUmkEtu1Pm2XmQ1S0o4GE6h1Ni29IiatKCSGLHUGLO9LkRqsPqgF5rSMw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Tue9wRNh; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Tue9wRNh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D4302C433B1; Thu, 25 Jan 2024 15:11:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706195516; bh=qqT5s5v8kHRYnSn/7vdNCIRU1OWwV2sCCtz6w1JM1Uc=; h=From:To:Cc:Subject:Date:From; b=Tue9wRNhjMqZFzK9146TlHqSh0uS3ptUAk+FbgZLPMoo5orbTE+F/5izGNNkfxOnL cSpfL9FJ7/q3eNwQhDZTh4C7UzTy5Rz2tGw84k3NlUHq0VtjAYRNS9NwXMWGgy6cBA 8Mv4z7gyOxW46+SAVZYb41ehlqkVFEqWK0AFEJLuq2QgX4+kDMfe45s5i9yfEa4dIF 6asoOd75OLoQXMMJQOhKt0DuCwVCycuNQgR2CaArJsLts1byjJ9bfGhbD+XTnLs5Ui zUJ8G/U2/VczZsQR+2qtSouhJn5K68Wty5B84vIVtkJbwdGsPq2SSkHIZvCWZgWfax PMXyVsmyAsroA== From: Jisheng Zhang To: Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 0/2] riscv: enable lockless lockref implementation Date: Thu, 25 Jan 2024 22:59:05 +0800 Message-ID: <20240125145908.968-1-jszhang@kernel.org> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit This series selects ARCH_USE_CMPXCHG_LOCKREF to enable the cmpxchg-based lockless lockref implementation for riscv. Then, implement arch_cmpxchg64_{relaxed|acquire|release}. After patch1: Using Linus' test case[1] on TH1520 platform, I see a 11.2% improvement. On JH7110 platform, I see 12.0% improvement. After patch2: on both TH1520 and JH7110 platforms, I didn't see obvious performance improvement with Linus' test case [1]. IMHO, this may be related with the fence and lr.d/sc.d hw implementations. In theory, lr/sc without fence could give performance improvement over lr/sc plus fence, so add the code here to leave performance improvement room on newer HW platforms. Link: http://marc.info/?l=linux-fsdevel&m=137782380714721&w=4 [1] Since v2: - rebase on v6.8-rc1 - collect Reviewed-by tag Since v1: - only select ARCH_USE_CMPXCHG_LOCKREF if 64BIT Jisheng Zhang (2): riscv: select ARCH_USE_CMPXCHG_LOCKREF riscv: cmpxchg: implement arch_cmpxchg64_{relaxed|acquire|release} arch/riscv/Kconfig | 1 + arch/riscv/include/asm/cmpxchg.h | 18 ++++++++++++++++++ 2 files changed, 19 insertions(+) -- 2.43.0