From patchwork Fri Dec 20 07:53:11 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yicong Yang X-Patchwork-Id: 13916332 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B9642E77188 for ; Fri, 20 Dec 2024 07:59:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=noM9PsIoqI0238JO/lKxLrjhK2pdRMsETmp8KFy9dQU=; b=BEVlqPiWZ7ycisQUkp7vBKiDre WT9hbQhpUS4jWPhp38jROLeUf40MaEU2e4q5ePaL8LeH0MlFwva4Om7jhNB652oIOldZFyrIp6PTu lbRlIoCzk5j4QyQjzXYrnkAjYTjt5ZuOwElNCd23mzIs5NG+45Ff+RJ4xfPKTF7yBOYuOQuFih+kV ygLi34y2PWCEm04Npa+rkSo83LY8Y7JKfNtPkpIUQ5RM9wxdymCL7xCL72ZlKX14sDN8yr43HgJ0/ 4iV87+temHc3XKMD1zvwCvAt3naG11sy0QqGHp9d9Io4vkb53/bR4F4rwai68wCZmYyn3vCU/guod 2neZM6Vg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tOXuc-00000004Dwg-1MiP; Fri, 20 Dec 2024 07:59:06 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tOXqA-00000004D8s-01ot for linux-arm-kernel@lists.infradead.org; Fri, 20 Dec 2024 07:54:31 +0000 Received: from mail.maildlp.com (unknown [172.19.163.44]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4YF03y1X41z1kwf5; Fri, 20 Dec 2024 15:51:42 +0800 (CST) Received: from kwepemd200014.china.huawei.com (unknown [7.221.188.8]) by mail.maildlp.com (Postfix) with ESMTPS id 1E1AB1402C4; Fri, 20 Dec 2024 15:54:19 +0800 (CST) Received: from localhost.localdomain (10.50.165.33) by kwepemd200014.china.huawei.com (7.221.188.8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.34; Fri, 20 Dec 2024 15:54:18 +0800 From: Yicong Yang To: , , , , , , , , , , , CC: , , , , , , , , , , , , Subject: [PATCH v10 2/4] arch_topology: Support SMT control for OF based system Date: Fri, 20 Dec 2024 15:53:11 +0800 Message-ID: <20241220075313.51502-3-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20241220075313.51502-1-yangyicong@huawei.com> References: <20241220075313.51502-1-yangyicong@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.50.165.33] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemd200014.china.huawei.com (7.221.188.8) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241219_235430_386973_667028A4 X-CRM114-Status: GOOD ( 16.56 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Yicong Yang On building the topology from the devicetree, we've already gotten the SMT thread number of each core. Update the largest SMT thread number and enable the SMT control by the end of topology parsing. The core's SMT control provides two interface to the users [1]: 1) enable/disable SMT by writing on/off 2) enable/disable SMT by writing thread number 1/max_thread_number If a system have more than one SMT thread number the 2) may not handle it well, since there're multiple thread numbers in the system and 2) only accept 1/max_thread_number. So issue a warning to notify the users if such system detected. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/ABI/testing/sysfs-devices-system-cpu#n542 Signed-off-by: Yicong Yang --- drivers/base/arch_topology.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 3ebe77566788..9e81060144c7 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -506,6 +507,10 @@ core_initcall(free_raw_capacity); #endif #if defined(CONFIG_ARM64) || defined(CONFIG_RISCV) + +/* Maximum SMT thread number detected used to enable the SMT control */ +static unsigned int max_smt_thread_num; + /* * This function returns the logic cpu number of the node. * There are basically three kinds of return values: @@ -565,6 +570,17 @@ static int __init parse_core(struct device_node *core, int package_id, i++; } while (1); + /* + * If max_smt_thread_num has been initialized and doesn't match + * the thread number of this entry, then the system has + * heterogeneous SMT topology. + */ + if (max_smt_thread_num && max_smt_thread_num != i) + pr_warn_once("Heterogeneous SMT topology is partly supported by SMT control\n"); + + if (max_smt_thread_num < i) + max_smt_thread_num = i; + cpu = get_cpu_for_node(core); if (cpu >= 0) { if (!leaf) { @@ -677,6 +693,16 @@ static int __init parse_socket(struct device_node *socket) if (!has_socket) ret = parse_cluster(socket, 0, -1, 0); + /* + * Notify the CPU framework of the SMT support. Initialize the + * max_smt_thread_num to 1 if no SMT support detected. A thread + * number of 1 can be handled by the framework so we don't need + * to check max_smt_thread_num to see we support SMT or not. + */ + if (!max_smt_thread_num) + max_smt_thread_num = 1; + + cpu_smt_set_num_threads(max_smt_thread_num, max_smt_thread_num); return ret; }