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 EE2FBCD1292 for ; Thu, 4 Apr 2024 18:57:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8E5B56B0098; Thu, 4 Apr 2024 14:57:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 896C86B0099; Thu, 4 Apr 2024 14:57:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7855C6B009A; Thu, 4 Apr 2024 14:57:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 5BC3D6B0098 for ; Thu, 4 Apr 2024 14:57:07 -0400 (EDT) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 21CD11A05C6 for ; Thu, 4 Apr 2024 18:57:07 +0000 (UTC) X-FDA: 81972756894.15.E60FDDE Received: from gentwo.org (gentwo.org [62.72.0.81]) by imf19.hostedemail.com (Postfix) with ESMTP id 842BE1A0004 for ; Thu, 4 Apr 2024 18:57:04 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=none; spf=softfail (imf19.hostedemail.com: 62.72.0.81 is neither permitted nor denied by domain of cl@linux.com) smtp.mailfrom=cl@linux.com; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=linux.com (policy=none) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1712257024; 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; bh=5hwmldRTY1MU9FBBmBtRZtYa0pOroo5z1tIEKizpDe4=; b=Fj+5crHl+LMbsZN+42SB8KgkQwgaedt28J2mRJfa8i5RbE8dl+Ll/WxStNNdXv/k9sYPBY 5b3NCpU5PGWZnvePZN18HqavYxeg7XfpdMVMgltKG2f1r2Y/urX5qwJiyPFLkEhryhPkoM EE1CVb5C+JZdlXuNGFsuugTU7DSfCuA= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=none; spf=softfail (imf19.hostedemail.com: 62.72.0.81 is neither permitted nor denied by domain of cl@linux.com) smtp.mailfrom=cl@linux.com; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=linux.com (policy=none) ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1712257024; a=rsa-sha256; cv=none; b=2kBTez0yVbOwHoc8It3DYCzLZJn5bPQ0ZCtn3aP3Xcot4FBUUEUMlghLBKMXsdAETO7m1+ 9EWEY3qyrFlbarE4iUCT9ioftnQXe57OmT2LqsGMr84qlq+LmUZF6qU0/mjmp+ywAtWy+D /AhyGXpUXhZxa1m1x7esbhQTPPDxR6k= Received: by gentwo.org (Postfix, from userid 1003) id 0704A40A86; Thu, 4 Apr 2024 11:57:03 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id 0658A408AA; Thu, 4 Apr 2024 11:57:03 -0700 (PDT) Date: Thu, 4 Apr 2024 11:57:03 -0700 (PDT) From: "Christoph Lameter (Ampere)" To: Jonathan Cameron cc: Yang Shi , lsf-pc@lists.linux-foundation.org, olivier.singla@amperecomputing.com, Linux MM , Michal Hocko , Dan Williams Subject: Re: [LSF/MM/BPF TOPIC] Multi-sized THP performance benchmarks and analysis on ARM64 In-Reply-To: <20240401191614.00007c83@Huawei.com> Message-ID: References: <20240401191614.00007c83@Huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed X-Rspamd-Queue-Id: 842BE1A0004 X-Rspam-User: X-Stat-Signature: 7kimpim3ydjpywyxujjcdbh6w9hssh5k X-Rspamd-Server: rspam01 X-HE-Tag: 1712257024-836345 X-HE-Meta: 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 8KW1QnVn V7EIScVo6ThcsJhXjVUo2kkdnZLBopR/vde8dbeYPYc1kY+U8KhQ/+FAFIsqNxHHUnnQwaWhACncq/yte4nK4LpEN7R3EDw/OYZI8EdO6g75uE8O7oyqEMxhBeprVSl+MrIWO X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, 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 Mon, 1 Apr 2024, Jonathan Cameron wrote: > Sounds like useful data, but is it a suitable topic for LSF-MM? > What open questions etc is it raising? mTHP is new functionality that will require additional work to support more use cases. It is also unclear at this point in what usecases mTHP is useful and where no benefit can so far be seen. Also the effect of coalescing multiple PTE entries into one TLB entry is new to MM (CONT_PTE). Ultimately it would be useful to have mTHP support also provide larger blocksize capabilities for filesystem etc etc. mTHP needs to mature and an analysis of the arguable a bit experimental state of affairs can help a lot in getting there.