From mboxrd@z Thu Jan 1 00:00:00 1970 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.subspace.kernel.org (Postfix) with ESMTPS id 8E6DC29E109; Wed, 3 Dec 2025 07:00:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764745211; cv=none; b=G9cweC4nPM2UJIFgdAKpk3sTUyL2NplFHiXwEogseXIK+G779jx+4yov1QtGmXPVRpJ3mhQ9fSy7yIgJOCN/ZGOlOkqAtedcelr7cCd1LIiIxyutVuTq9NjmmfqfPMYNa7DwnDHoVMODhNXEz41GswLy99AFDZCVZwc9kSTG1vg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764745211; c=relaxed/simple; bh=I5lf7g0xAOjWdU4ZyjRV66iHrvV3tSj8kM6QDX2HKSU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gsP7qmtK4UtLVNZledmfrB1vD1r0XSr0HQpzMfKqfRlynI9qxz+Ainw6cr9CBp7CPAKRJlDJ63HrDCY84xQGKMh+wcwfgvCDbGaW3GxmqpCWctHQYh7iS/EqQ5b9uiqU71VMucqAg+3tV+asEIUzxZPKj31qFoipYc1vVi0k+TY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=fhqh+UEy; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="fhqh+UEy" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=VJqpFrVujNbKhtLoEDTUT5PqTMsA91l6sKEhJ89/1So=; b=fhqh+UEyWf1H7LwNPksaUrPjOy A0GvlFFbiKqKrHwxpVOvmAu+L/mrm52mkA9IyWGSTtQqmDPo6slwsk1Uif5XD8JbrGOcQiyOh0RHd AB7aYa2O/JBkP/oG4wwdon+VB5WNRqcwVA+RhmFmbhEIfK7Sn1ViK5h7HNWx9nsdGZr0kHCsr5X3Y youmnGHyIpKZvnG+ChqMtx+vNQGUm4bryNYGGsqiH/55Yyl7s6xDfoizMbQD2dsdQuSFDo5m4fupH WGjcssRUpaXpjmIi8w9fc+UK316V+4PiiNc3nAvllbDK83wVFQPdbSXPwEomXasacD07kxshQRxqJ XCwUJUSg==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vQgqL-00000006EGM-1ddu; Wed, 03 Dec 2025 07:00:05 +0000 Date: Tue, 2 Dec 2025 23:00:05 -0800 From: Christoph Hellwig To: Jani Partanen Cc: Christoph Hellwig , Giovanni Cabiddu , clm@fb.comi, dsterba@suse.com, terrelln@fb.com, herbert@gondor.apana.org.au, linux-btrfs@vger.kernel.org, linux-crypto@vger.kernel.org, qat-linux@intel.com, cyan@meta.com, brian.will@intel.com, weigang.li@intel.com, senozhatsky@chromium.org Subject: Re: [RFC PATCH 00/16] btrfs: offload compression to hardware accelerators Message-ID: References: <20251128191531.1703018-1-giovanni.cabiddu@intel.com> <8d3e44b0-23d8-4493-8e7e-33bbe1d904ef@sotapeli.fi> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8d3e44b0-23d8-4493-8e7e-33bbe1d904ef@sotapeli.fi> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Tue, Dec 02, 2025 at 05:46:29PM +0200, Jani Partanen wrote: > > On 02/12/2025 9.53, Christoph Hellwig wrote: > > On Fri, Nov 28, 2025 at 07:04:48PM +0000, Giovanni Cabiddu wrote: > > > +---------------------------+---------+---------+---------+---------+ > > > | | QAT-L9 | ZSTD-L3 | ZLIB-L3 | LZO-L1 | > > > +---------------------------+---------+---------+---------+---------+ > > > | Disk Write TPUT (GiB/s) | 6.5 | 5.2 | 2.2 | 6.5 | > > > +---------------------------+---------+---------+---------+---------+ > > > | CPU utils %age @208 cores | 4.56% | 15.67% | 12.79% | 19.85% | > > > +---------------------------+---------+---------+---------+---------+ > > > | Compression Ratio | 34% | 35% | 37% | 58% | > > > +---------------------------+---------+---------+---------+---------+ > > Is it just me, or do the numbers not look all that great at least > > when comparing to ZSTD-L3 and LZO-L1? What are the decompression > > numbers? > > > > What makes you think so? Well, if you compared QAT-L9 to LZO-L1 specifically: - yes, cpu usage is reduced to a quarter - disk performance is the same - the compression ratio is much, much worse and we don't know anything about the decompression speed. All the while you significantly complicate the code.