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See http://www.infradead.org/rpr.html X-Headers-End: 1wS7ku-0003oV-4b Subject: Re: [f2fs-dev] [PATCH v2] f2fs: another way to set large folio by remembering inode number X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Theodore Tso , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, Matthew Wilcox , linux-f2fs-devel@lists.sourceforge.net, Christoph Hellwig , linux-mm@kvack.org, Akilesh Kailash , linux-fsdevel@vger.kernel.org, Jaegeuk Kim , Christian Brauner Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Tue, May 26, 2026 at 09:14:52AM -0700, Bart Van Assche wrote: > 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. I'm honestly not sure what discussion we have here. Larger I/O is pretty much always more efficient. If you submit smaller I/O you need more merging to build it back up larger, and more I/Os. Which is exaxtly why we need large folio support everywhere, as it makes a huge difference in I/O performance. _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel