From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 011.lax.mailroute.net (011.lax.mailroute.net [199.89.1.14]) (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 1F8013AF643; Tue, 26 May 2026 16:15:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=199.89.1.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779812103; cv=none; b=odPmSGHXgl+kEscvHlNU5Qzi8V/X6LSyKpC0rUAofa22HP7FiFzkysQl13e1KsgG+mPf3ZOpjywzQBC0ffiflfbLvfKRCoMkHtWoH0bZzvsYTt211vsZ2wauD0qLEwF/Pxcess9FuOPSh8tFtRPaThedAIzpQUq1wO44SzG4uZk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779812103; c=relaxed/simple; bh=WPbX4Pya39Go2QYFfMt8pFd9wdKpwRyohHZi0oibzRg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=VrvdHvoGHwAHbqqt8d964A5211YzGJxu6o9AuVhhPyBOPzx2ZqKwAwP79vr9VRDEuIQL9G9YHQFpjn/n9ykWc9Ut+Fk0580ky4OmadZzFCLuq1XWiAKlqteioYaumV60D1ulYqQnlyuL2OhjKI4knTerzSbu2Dz93kQ360mSuNo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org; spf=pass smtp.mailfrom=acm.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b=AwiokLBm; arc=none smtp.client-ip=199.89.1.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=acm.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b="AwiokLBm" Received: from localhost (localhost [127.0.0.1]) by 011.lax.mailroute.net (Postfix) with ESMTP id 4gPyWn3BVxz1XM6JN; Tue, 26 May 2026 16:15:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=acm.org; h= content-transfer-encoding:content-type:content-type:in-reply-to :from:from:content-language:references:subject:subject :user-agent:mime-version:date:date:message-id:received:received; s=mr01; t=1779812096; x=1782404097; bh=Anhq5FjNw5ss6qMVPZ01kvuQ c5NdyWfGRn2xYsjiF0E=; b=AwiokLBmkPXRDvxv4gU5Q8BxVUMZRQTyw3y+Qzdh Z784kR81SRXa82sIkwXcsNyi3LSlK1dqku6rTPoMoPVmLytdqkrK3Yk8LKaof1z5 IUvPNNPc/Q6S7kOjZkbSrACPm7bjIjgzu1IxxbKBQSlK4tuv38BU7fvs8dD3euDA Tw4fggBiI1+wbtfQf2lxAk1Mu/LOduAx3pQdID/Ykhu4h1DH/J12zN1DDyjiiSdq XX0cpwgKDWTwyPidFJSdYB7dm+oZ0m3I2dTqtBYofc2bGINuwLNf+Ojxd6k3KQ2K xZpeQClWswqs2VOXACuw4RtpJCE1iU/Qha8dSaZmA5A3hg== X-Virus-Scanned: by MailRoute Received: from 011.lax.mailroute.net ([127.0.0.1]) by localhost (011.lax [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id zKWCJmXtLFCk; Tue, 26 May 2026 16:14:56 +0000 (UTC) Received: from [100.119.48.131] (unknown [104.135.180.219]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bvanassche@acm.org) by 011.lax.mailroute.net (Postfix) with ESMTPSA id 4gPyWd3bBJz1XM5jn; Tue, 26 May 2026 16:14:53 +0000 (UTC) Message-ID: Date: Tue, 26 May 2026 09:14:52 -0700 Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [f2fs-dev] [PATCH v2] f2fs: another way to set large folio by remembering inode number To: Theodore Tso , Jaegeuk Kim Cc: linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, Matthew Wilcox , linux-f2fs-devel@lists.sourceforge.net, Christoph Hellwig , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Akilesh Kailash , Christian Brauner References: <20260521155748.GA79343@macsyma-wired.lan> <20260522141115.GA8258@macsyma-wired.lan> <20260522224108.GA18663@macsyma-wired.lan> Content-Language: en-US From: Bart Van Assche In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 5/26/26 6:42 AM, Theodore Tso wrote: > It seems... surprising that the additional I/O operations are actually > throttloing UFS device bandwidth by 2x (4GB/s vs 2GB/s). Have you dug > into why this is happening, and whether there is anything that can be > optimized below the file system? The layers below the filesystem (block, SCSI, UFS) is what I'm responsible for in the Pixel team and I can assure you that these are highly optimized. Since the transfer size used in Jaegeuk's tests is much larger than 4 KiB, how many CPU cycles are used per IO by the layers below the filesystem is not limiting the transfer bandwidth. Bart.