From mboxrd@z Thu Jan 1 00:00:00 1970 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A8C7C36010 for ; Tue, 8 Apr 2025 21:14:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CEF0F6B00B6; Tue, 8 Apr 2025 17:14:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C9E936B00B9; Tue, 8 Apr 2025 17:14:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B651B6B00BB; Tue, 8 Apr 2025 17:14:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 9888E6B00B6 for ; Tue, 8 Apr 2025 17:14:52 -0400 (EDT) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 256E2C0817 for ; Tue, 8 Apr 2025 21:14:54 +0000 (UTC) X-FDA: 83312131308.02.A741669 Received: from gentwo.org (gentwo.org [62.72.0.81]) by imf05.hostedemail.com (Postfix) with ESMTP id 72B77100003 for ; Tue, 8 Apr 2025 21:14:52 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=gentwo.org header.s=default header.b=pbfovDHk; spf=pass (imf05.hostedemail.com: domain of cl@gentwo.org designates 62.72.0.81 as permitted sender) smtp.mailfrom=cl@gentwo.org; dmarc=pass (policy=reject) header.from=gentwo.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1744146892; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=WG+cj5i1GbTabFslLXYHUzovUuREFvJlBBWLxyJtbIo=; b=BIwL53mLrYEKez4soJ/UrypeS2emlatAf0wTmNR+dj8F8zARomwT9GSfxwQV1lN4y2aldG iH0rkNQgQQM2xjRpAWLQmJ8u0bBb0e1FKanXy+nSSwyAXMa1EdxU7XlBXeKZDDVkq2MbHe Sql99xoRO6pytENzvoNSNySKpI1zo6A= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=gentwo.org header.s=default header.b=pbfovDHk; spf=pass (imf05.hostedemail.com: domain of cl@gentwo.org designates 62.72.0.81 as permitted sender) smtp.mailfrom=cl@gentwo.org; dmarc=pass (policy=reject) header.from=gentwo.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1744146892; a=rsa-sha256; cv=none; b=64caf+LG5bmQwZW2y3rpnf/ybDhuj6FgLfyCO80NfXrJDu9zfPduY4KwCsbtV8J5y/ct/B LKGGKaN98CEp0idhuFcYKRPxgKYa5lf26mGXZE87xzdKwsCLRVL7e8Kxtjh3wZMoAKz6z1 mfbfGUl/dFz+BDCWX642/SNO0sah+pI= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gentwo.org; s=default; t=1744145065; bh=WG+cj5i1GbTabFslLXYHUzovUuREFvJlBBWLxyJtbIo=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=pbfovDHk6lOSLkh5+VshEKxpw9B2s+e5b5FfhUL4EZnfD3cJ8DoosczLAsisV8yLW umFdiuqcSaxDGjjDJMEhONIexkS5nTlxQhV+7rIZqunpDswAg7lrxgRJaepklVq5uH AaB6mcgkwWIipDh4qnIq7YInk1uNnee2r6rFR1L0= Received: by gentwo.org (Postfix, from userid 1003) id 51AF04028A; Tue, 8 Apr 2025 13:44:25 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id 4EEF6401F1; Tue, 8 Apr 2025 13:44:25 -0700 (PDT) Date: Tue, 8 Apr 2025 13:44:25 -0700 (PDT) From: "Christoph Lameter (Ampere)" To: Mathieu Desnoyers cc: Sweet Tea Dorminy , Mateusz Guzik , linux-kernel@vger.kernel.org, Andrew Morton , "Paul E. McKenney" , Steven Rostedt , Masami Hiramatsu , Dennis Zhou , Tejun Heo , Martin Liu , David Rientjes , christian.koenig@amd.com, Shakeel Butt , Johannes Weiner , Lorenzo Stoakes , "Liam R . Howlett" , Suren Baghdasaryan , Vlastimil Babka , Christian Brauner , Wei Yang , David Hildenbrand , Miaohe Lin , Al Viro , linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, Yu Zhao , Roman Gushchin , Matthew Wilcox Subject: Re: [RFC PATCH v2] Introduce Hierarchical Per-CPU Counters In-Reply-To: Message-ID: References: <20250408160508.991738-1-mathieu.desnoyers@efficios.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspamd-Queue-Id: 72B77100003 X-Rspamd-Server: rspam05 X-Rspam-User: X-Stat-Signature: qgtnqz74o1xoxdgwbo9zkytbxuayeb1m X-HE-Tag: 1744146892-739309 X-HE-Meta: U2FsdGVkX1/fcGA+UO2CkDj3KTWOoWY/5sOVfgQET7PokJp27y734M/842UGDPonc+fUt/d6FbNs80twNSGRpoqncFF6fuNLmdn8I3Nksgki43vBTZ5oQVLskad8QHb/+hJdtksXJ86Vgrv/ppW8YrARI02KWeGeOazSItkMazV46ydr7N00r74NpdkW30pnsPfinQsg4le8285zN34chaNYQsxo7v5fZAgHJUYPOThGafTkYkFn0x6AgI0u7d+wPV8QuCM7JeD0+3MecKrht5Hm2RS40KHsPjvE/Evr0zCX01PyTCIyeOhESe6jTG5DD79q+nluohzpwqsxZyYP9IGWVWm/sG4Sop9zJU3K1T1ttH/5VtCzfxI9TzOliw3eHz+swfGN5wRQnaw3Uh9eudSN17rgYxxgoxDUQX0xOmIgoHKHyU3zSL8cI4F6gfdmZRnsVTXoDC/uIDyk6D+m16ZStCNMnozNZtrIWTmslR8RLiYl5ughpSvJ+B8ea4fZZ0gH7vFze0sKpn5H//iAjHWPv2S3pmeoTa8pZxomqvVhH6qaS1BL5vT5nUARfEw4JmPPsgLGt3FAoC/lWDZ92uc8LDI+YNWccajEST+I2ZIXR2jDSES/MP7Uq2MOHq5YBEajPgHs0Jp8IHrV/I4twazZ6Fj6C2JhGAv9xYADVNtWqbkm9jJ9VG0RbXQd8FFoq+kr4zerlsiUgNQxz1qRxQeE0DCVnNPIZ5WqexUfPsFO6WEOVBZ4JJ7gaxbHueLf5M3++J20p4RHbS1UstpwyIDewRBv2CE3AXNUtgB7Z/11zBBMYSWBMaFQallPmzSTbHFS1+cvAg3Qdzw7HKjKwmLMLu05V9kaRId+LiaHLvDP+jEQqOlisgQzFglp2oIHU/aO6NI1rezKGjNL77E98wgT7KD9hib94mjT/n2Q/qjs2+uHmefzxmZ7IobMK/v8GHH66vjJmDG4n8xziSO DBZMZKs1 FDDNJG04wxMunCjr878QH6ap+hfQVUVAZhXZRh3mYN5oKDvsEkl7WmczJgdbDPY134Hd0AxkI3DhJJJmPQOxCVml2GlekgZbijCvf7nvLaMTl86gQzNPOjalEFWTl56mPVVCF9FtJnl14vGx5SXcLTnDHCnUwLwkzerAQ4qtECk1ZwBbNZCaj3nnWykYWLGrydmctrbjpJJHpxxp06r+EkhywJG6lmRfJmazJU/TDiGhe2ndTowatuuo3cQDhl+oMgJIDvs+k1WqZtMCN9+ravkC8x0vvI6uDc+l1160jBPSlQpUzdKZ0UEumT5XQVdC5awTW X-Bogosity: Ham, tests=bogofilter, spamicity=0.000003, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 8 Apr 2025, Mathieu Desnoyers wrote: > Currently percpu_counter_tree_precise_sum_unbiased() iterates on each > possible cpu, which does not require cpu hotplug integration. Well that looks like a performance issue if you have a system that can expand to 8K cpus but currently only has 16 or so online.