From patchwork Tue Nov 5 09:32:35 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yicong Yang X-Patchwork-Id: 13862728 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 7ABC1D12674 for ; Tue, 5 Nov 2024 09:47:11 +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=uYynWeIqGbf3qbAfwEFwOheYS274s3APdK2N0xWvl/8=; b=d99QzGcf0GZqD0zmF0xep29TeZ JskmKi8hZQrXkUttU+RM+nwbQZf2o0UmYmTZUL3yP98Lq3UewfD2QydMFjOoRNncZHE9bSzQZVt64 Oso/TqkLMozZaUmkGBJYsIy7bkFP4YFjz6xIh00ZijqWbrBKsOCU/JlZ3adLkBetJijmjPg3MiFIp VRina1XSFt2/ZPvc+WF3U2Ayo5sa/9SQK/ys1q/RBsjO+E9sUgcfQQaD9ZXB43lKn3LLvLnz2NZan I5SmFU3smgQLLvjaX1TEvRPLXrJOkYLzQXlNFpUJhI8OrurqBEt8Fll1cN3uDqg7eUkrPXAn9Ze8S bqtgkepA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t8G9I-0000000GZ3B-3vmy; Tue, 05 Nov 2024 09:46:56 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t8Fw6-0000000GWTO-1xhF for linux-arm-kernel@lists.infradead.org; Tue, 05 Nov 2024 09:33:21 +0000 Received: from mail.maildlp.com (unknown [172.19.163.174]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4XjNP825WLz10Pf8; Tue, 5 Nov 2024 17:30:52 +0800 (CST) Received: from kwepemd200014.china.huawei.com (unknown [7.221.188.8]) by mail.maildlp.com (Postfix) with ESMTPS id 2AFE914038F; Tue, 5 Nov 2024 17:33:11 +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, 5 Nov 2024 17:33:10 +0800 From: Yicong Yang To: , , , , , , , , , , , CC: , , , , , , , , , , , , Subject: [PATCH v8 2/4] arch_topology: Support SMT control for OF based system Date: Tue, 5 Nov 2024 17:32:35 +0800 Message-ID: <20241105093237.63565-3-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20241105093237.63565-1-yangyicong@huawei.com> References: <20241105093237.63565-1-yangyicong@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.50.165.33] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) 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-20241105_013319_613791_59F01B9B X-CRM114-Status: GOOD ( 18.12 ) 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 | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 75fcb75d5515..e2c8e6d92414 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -502,6 +503,10 @@ 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: @@ -561,6 +566,17 @@ 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) { @@ -673,6 +689,14 @@ 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; }