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 4D60DC0219E for ; Tue, 11 Feb 2025 17:05:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B23C7280002; Tue, 11 Feb 2025 12:05:20 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AD3AE280001; Tue, 11 Feb 2025 12:05:20 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9C3B3280002; Tue, 11 Feb 2025 12:05:20 -0500 (EST) 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 4A7F8280001 for ; Tue, 11 Feb 2025 12:05:20 -0500 (EST) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id D40991A06C9 for ; Tue, 11 Feb 2025 17:05:18 +0000 (UTC) X-FDA: 83108289516.09.E016685 Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by imf01.hostedemail.com (Postfix) with ESMTP id B2F0340015 for ; Tue, 11 Feb 2025 17:05:16 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=mBdf+Ih1; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf01.hostedemail.com: domain of ebiggers@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=ebiggers@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1739293516; a=rsa-sha256; cv=none; b=bb4QiUcuD++Ixld3ljGbUfCKLTJfKD2hPWVner/LkvYKuF+J9O7foFUD6Cgf9Uhzigc/Yq U8NIY7yuy3fWZ97FRqeklbx75jOR2n/iEKa50/Iz5P/UIq8QouhwKV9QfYOQhzo0nVWmIk IBeNUdiHTjCNzNyvCY3+F/JAEfawOHI= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=mBdf+Ih1; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf01.hostedemail.com: domain of ebiggers@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=ebiggers@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1739293516; 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=SF2Soh7XCJR6DYw11KLwZQcPsD8bci0XDcEjctfsAZE=; b=nnj/QaS0T0nZB/Q+Pkgq1zqtWsVxyAcZaxlOFljFB0cOBvI5rb9tS64hlf+D7+faUQGixI NAhoFLVqRWLWG8quwhrUknQx5TMXM3KfW3wX0mCiSxGtlceLNDG64HJq3PgoevOh3MRDK2 55mEPMMMXIAnf0e/W19gyESCMuEwexc= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 54352A408A8; Tue, 11 Feb 2025 17:03:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E328CC4CEDD; Tue, 11 Feb 2025 17:05:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739293515; bh=4SlwwWxS+SQPd/d/oR8xE4I/YSQQ0zoz8M3b8E1zjEw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mBdf+Ih1kmF4vUqTTwGdNBZW1z5ZtYlGN9Kh6h5Gk5GhSITdAVnJPI6X6ephobZNV hos0cutdV7vSuPGGlstWzPG9Kvn7ZIMgJil6bGWg0cUUmp07Wce1WBsK3AUpU+WxeY iMHkw7qzR78mKym7mwM9oukCpMwUmAdw9jASVA3ZjiHEw/cahlZPna0Fpm4sZfmuid fSPRg7tcveI4gATGV9y28wo++LFYoqM7al68GG2FaQel8Sh2S2edpAubVwe7D9JE1D tiHk93fnPPxWR2j0nC8rEU72HvMlGhSFP/eFEn3MdibI33N4fEbj5/BW+Ir+9x+HjN PBwHo/3BR1nwA== Date: Tue, 11 Feb 2025 09:05:13 -0800 From: Eric Biggers To: Kanchana P Sridhar Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, hannes@cmpxchg.org, yosry.ahmed@linux.dev, nphamcs@gmail.com, chengming.zhou@linux.dev, usamaarif642@gmail.com, ryan.roberts@arm.com, 21cnbao@gmail.com, akpm@linux-foundation.org, linux-crypto@vger.kernel.org, herbert@gondor.apana.org.au, davem@davemloft.net, clabbe@baylibre.com, ardb@kernel.org, surenb@google.com, kristen.c.accardi@intel.com, wajdi.k.feghali@intel.com, vinodh.gopal@intel.com Subject: Re: [PATCH v6 00/16] zswap IAA compress batching Message-ID: <20250211170513.GB1227@sol.localdomain> References: <20250206072102.29045-1-kanchana.p.sridhar@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250206072102.29045-1-kanchana.p.sridhar@intel.com> X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: B2F0340015 X-Stat-Signature: cjwuahrqnystgkj7d4mkco3aye1x9u7g X-Rspam-User: X-HE-Tag: 1739293516-786566 X-HE-Meta: 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 BiIqYDPT iV1Ovy6MuLblD12kzcz91n3dKrAcSlwPFhAZW/UP1fuydHrrz6BmaBWStIuJO7sVG3ohhzj6ufZ3tZLzDnuPKORAG74V0HUOoJWluidA6ybpP6EL0r1BQTPwQCHl38gNXDS41kn3BCfLcJ6qEoQfENe+XVWfBoJO9sQN1CJCLPr+vTeLUMrD2e5Y2lGmNvIIg/0qb9BC5GsGo4X+KObnl2rMeiQ== 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 Wed, Feb 05, 2025 at 11:20:46PM -0800, Kanchana P Sridhar wrote: > IAA Compression Batching: > ========================= > > This patch-series introduces the use of the Intel Analytics Accelerator > (IAA) for parallel batch compression of pages in large folios to improve > zswap swapout latency. So, zswap is passed a large folio to swap out, and it divides it into 4K pages and compresses each independently. The performance improvement in this patchset comes entirely from compressing the folio's pages in parallel, synchronously, using IAA. Before even considering IAA and going through all the pain of supporting batching with an off-CPU offload, wouldn't it make a lot more sense to try just compressing each folio in software as a single unit? Compared to the existing approach of compressing the folio in 4K chunks, that should be much faster and produce a much better compression ratio. Compression algorithms are very much designed for larger amounts of data, so that they can find more matches. It looks like the mm subsystem used to always break up folios when swapping them out, but that is now been fixed. It looks like zswap just hasn't been updated to do otherwise yet? FWIW, here are some speed and compression ratio results I collected in a compression benchmark module that tests feeding vmlinux (uncompressed_size: 26624 KiB) though zstd in 4 KiB page or 2 MiB folio-sized chunks: zstd level 3, 4K chunks: 86 ms; compressed_size 9429 KiB zstd level 3, 2M chunks: 57 ms; compressed_size 8251 KiB zstd level 1, 4K chunks: 65 ms; compressed_size 9806 KiB zstd level 1, 2M chunks: 34 ms; compressed_size 8878 KiB The current zswap parameterization is "zstd level 3, 4K chunks". I would recommend "zstd level 1, 2M chunks", which would be 2.5 times as fast and give a 6% better compression ratio. What is preventing zswap from compressing whole folios? - Eric