From patchwork Tue Oct 15 02:18:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yicong Yang X-Patchwork-Id: 13835669 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 74AD1CFC505 for ; Tue, 15 Oct 2024 02:20:50 +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=YumWRjLsN6h/LN46DP70XOCjZCBfFNHu9orkVhFqpbk=; b=ZedTu2ILoOQMy5bYVilcpfDQLr P6PAyPIzOtC7AMZ7Zt8ya1VpFx1SXrDDd9NkAKPvV2pXLTbCMSw4oOmoU+9acDx6kvJ18DZlRh1CI X6/yyh07XpifRbItnaMPg8MPHMtevEjVNYdBoi1boj5AlFF3oj39K53IHh4s2zcTGVFtMaZZToeJC pOI8e3Y1xWKqRYkmQ7zUPukCXQoPzIPUo2GNswj9EpeBC8W7TamiCXi6W+scGdcIyPIY84lY0Z4i8 BehoFbckzyOLJZyELV4ORGA8xpFkHeP6bcoYsU8eS8rS9hPnrp/4unO+FfBltf6JccZ5jbCfUt6Bb DkZzwR/A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t0XAs-00000006rwj-1SIX; Tue, 15 Oct 2024 02:20:38 +0000 Received: from szxga06-in.huawei.com ([45.249.212.32]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t0X9R-00000006rbu-36Om for linux-arm-kernel@lists.infradead.org; Tue, 15 Oct 2024 02:19:11 +0000 Received: from mail.maildlp.com (unknown [172.19.162.112]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4XSHpd5cThz1ymC8; Tue, 15 Oct 2024 10:19:05 +0800 (CST) Received: from kwepemd200014.china.huawei.com (unknown [7.221.188.8]) by mail.maildlp.com (Postfix) with ESMTPS id 2DE6A1400D4; Tue, 15 Oct 2024 10:19:00 +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; Tue, 15 Oct 2024 10:18:59 +0800 From: Yicong Yang To: , , , , , , , , , , , CC: , , , , , , , , , , , , Subject: [PATCH v6 2/4] arch_topology: Support SMT control for OF based system Date: Tue, 15 Oct 2024 10:18:39 +0800 Message-ID: <20241015021841.35713-3-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20241015021841.35713-1-yangyicong@huawei.com> References: <20241015021841.35713-1-yangyicong@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.50.165.33] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) 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-20241014_191910_257478_A3C9949E X-CRM114-Status: GOOD ( 17.54 ) 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 | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 75fcb75d5515..5eed864df5e6 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -28,6 +29,7 @@ static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data); static struct cpumask scale_freq_counters_mask; static bool scale_freq_invariant; +static unsigned int max_smt_thread_num; DEFINE_PER_CPU(unsigned long, capacity_freq_ref) = 1; EXPORT_PER_CPU_SYMBOL_GPL(capacity_freq_ref); @@ -561,6 +563,17 @@ static int __init parse_core(struct device_node *core, int package_id, i++; } while (1); + if (max_smt_thread_num < i) + max_smt_thread_num = i; + + /* + * 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"); + cpu = get_cpu_for_node(core); if (cpu >= 0) { if (!leaf) { @@ -673,6 +686,14 @@ 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. 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) + cpu_smt_set_num_threads(max_smt_thread_num, max_smt_thread_num); + return ret; }