From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6EEBA2D9EEA; Fri, 31 Oct 2025 17:56:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761933381; cv=none; b=uahYAWYRsuIWg15IRPXO8f1F9gk4YnvT1LBTSjMmb5FT0s6VNDsjWiQDzADDxKhqdgEc26CXIEJ9GVWCowU3EmpSIvcJtBAkId6sldG5QIchpi1zsThOOjrZ4UkW+CtZouJgpSFa2t16JQKk3G8FeX2wTS+9gYsSF3f9q3R8USc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761933381; c=relaxed/simple; bh=H8EOJ2c9jd/Ul9NUBVR9luEIoA6uBvTNnShszv4+CP0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lzbcof90AYpmTF8poT7iJxtn6CnkyY34GTHi4YcdrbqD2JgPbVBexJib4aP6WwFz9QS5JaouA2sZh7TLLREZvZi12l90/gDl2r9UyzYy4Pm3GTduPUHSQvV7fnWBVWRflUhPZx3pMBRUhNCeb/KA1Zi+hDCsqOvLOJ4sSfAubx4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QwR8XQCT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QwR8XQCT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 436F9C4CEE7; Fri, 31 Oct 2025 17:56:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761933381; bh=H8EOJ2c9jd/Ul9NUBVR9luEIoA6uBvTNnShszv4+CP0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QwR8XQCTNs4U8EsVE1Fg2wPP+weaLRoD6a5DODzvC0Z8NwObu7FkFdEANlXb87c/7 hu5yR9UhR1X0JfraXrX+GNRSo6ty+Ex9S1PveeK7iB/8v3AYOy+keSd7jybWdgG2oc ubXLfON/hD43M4BNqjCrmzssfwpimah/k7B0q3YiAdLYlE37JHoh6ALZXGB0ib0EXX i6M3u/646FMz9uf+gNwXBp22GH4lcin2ejyoAHP4WminI+h+TLUWXlivMjp4GlgKUJ qSK3UeqR73ZiyVuQtKfOwtJcT/2nvKka48gWBunYrS2CLjem3cdOcU4N0OUxUtiH96 rFsGnhYxPrJFg== Date: Fri, 31 Oct 2025 10:56:20 -0700 From: "Darrick J. Wong" To: Joanne Koong Cc: linux-fsdevel , Miklos Szeredi , Bernd Schubert , linux-ext4 , Theodore Ts'o , Neal Gompa , Amir Goldstein , Christian Brauner , Jeff Layton Subject: Re: [PATCHBOMB v6] fuse: containerize ext4 for safer operation Message-ID: <20251031175620.GQ6174@frogsfrogsfrogs> References: <20251029002755.GK6174@frogsfrogsfrogs> Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Oct 30, 2025 at 09:35:25AM -0700, Joanne Koong wrote: > On Tue, Oct 28, 2025 at 5:27 PM Darrick J. Wong wrote: > > > > At this stage I still get about 95% of the kernel ext4 driver's > > streaming directio performance on streaming IO, and 110% of its > > streaming buffered IO performance. Random buffered IO is about 85% as > > Do you know why this is faster than ext4 sequential buffered IO? The last time I looked, ext4 still uses buffer heads and 4k folios, even for regular files that don't have any fancy features. IOWs, the iomap port for kernel ext4 remains unmerged. --D > Thanks, > Joanne > > > fast as the kernel. Random direct IO is about 80% as fast as the > > kernel; see the cover letter for the fuse2fs iomap changes for more > > details. Unwritten extent conversions on random direct writes are > > especially painful for fuse+iomap (~90% more overhead) due to upcall > > overhead. And that's with (now dynamic) debugging turned on! > > >