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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5349AC433EF for ; Fri, 8 Apr 2022 07:12:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229669AbiDHHO5 (ORCPT ); Fri, 8 Apr 2022 03:14:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34872 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229513AbiDHHOu (ORCPT ); Fri, 8 Apr 2022 03:14:50 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D3A6420A395 for ; Fri, 8 Apr 2022 00:12:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1649401966; x=1680937966; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=p9Vyinh/bxnpuA3ME5EXESNvBi6g7SL/nHb8H8N/Zz8=; b=ePexQnROL3G4KQQ3B15Ff9kELllKmc28Ipba+tahoGmZ0xwrfFsrzZ+Z Lq08Zsb5rs8P7xVLW5ogTM6xZ9U5uQ55lMRv0ygiDTcjFptdZZ7Mt1FAp FdDI+Zbe5WdoKwv73K4r/lONH4JW4AxBg8nYT1Uw6ybw66yZGiHRaqEui UkQYmWh/DKfeQSH3kkTITQlpRX5o0urNb9LBNLQqP9O7BNh1v3qpvgZRE InDnq+3lJjgqmOMlX9wzRU1+M4ZybA9MEXEAnvvHro96nYxwICTe6CmGr 2NXZf5ZWNoZWYSyfMiy/k4IgXHm2PVGTaYjCGGcGLaobNkQZhg9c02dKz Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10310"; a="261524670" X-IronPort-AV: E=Sophos;i="5.90,244,1643702400"; d="scan'208";a="261524670" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Apr 2022 00:12:46 -0700 X-IronPort-AV: E=Sophos;i="5.90,244,1643702400"; d="scan'208";a="550403934" Received: from fangyaxu-mobl.ccr.corp.intel.com (HELO yhuang6-mobl1.ccr.corp.intel.com) ([10.254.214.217]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Apr 2022 00:12:42 -0700 From: Huang Ying To: Peter Zijlstra , Mel Gorman , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Michal Hocko , Rik van Riel , Dave Hansen , Yang Shi , Zi Yan , Wei Xu , osalvador , Shakeel Butt , Zhong Jiang Subject: [PATCH 0/3] memory tiering: hot page selection Date: Fri, 8 Apr 2022 15:12:19 +0800 Message-Id: <20220408071222.219689-1-ying.huang@intel.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org To optimize page placement in a memory tiering system with NUMA balancing, the hot pages in the slow memory node need to be identified. Essentially, the original NUMA balancing implementation selects and promote the mostly recently accessed (MRU) pages. But the recently accessed pages may be cold. So in this patchset, we implement a new hot page identification algorithm based on the latency between NUMA balancing page table scanning and hint page fault. And the hot page promotion can incur some overhead in the system. To control the overhead a simple promotion rate limit mechanism is implemented. The hot threshold used to identify the hot pages is workload dependent usually. So we also implemented a hot threshold automatic adjustment algorithm. The basic idea is to increase/decrease the hot threshold to make the number of pages that pass the hot threshold (promote candidate) near the rate limit. We used the pmbench memory accessing benchmark tested the patchset on a 2-socket server system with DRAM and PMEM installed. The test results are as follows, pmbench score promote rate (accesses/s) MB/s ------------- ------------ base 146887704.1 725.6 hot selection 165695601.2 544.0 rate limit 162814569.8 165.2 auto adjustment 170495294.0 136.9 >From the results above, With hot page selection patch [1/3], the pmbench score increases about 12.8%, and promote rate (overhead) decreases about 25.0%, compared with base kernel. With rate limit patch [2/3], pmbench score decreases about 1.7%, and promote rate decreases about 69.6%, compared with hot page selection patch. With threshold auto adjustment patch [3/3], pmbench score increases about 4.7%, and promote rate decrease about 17.1%, compared with rate limit patch. Best Regards, Huang, Ying