From: "Martin K. Petersen" Subject: Re: [PATCH v1 00/16] ext4: Add metadata checksumming Date: Tue, 06 Sep 2011 08:59:53 -0400 Message-ID: References: <20110901003030.31048.99467.stgit@elm3c44.beaverton.ibm.com> <20110902182214.GC12086@tux1.beaverton.ibm.com> <20110905184524.GQ12086@tux1.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain Cc: "Martin K. Petersen" , Greg Freemyer , Andreas Dilger , Theodore Tso , Sunil Mushran , Amir Goldstein , linux-kernel , Andi Kleen , Mingming Cao , Joel Becker , linux-fsdevel , linux-ext4@vger.kernel.org, Coly Li To: djwong@us.ibm.com Return-path: Received: from rcsinet15.oracle.com ([148.87.113.117]:51482 "EHLO rcsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751956Ab1IFNA4 (ORCPT ); Tue, 6 Sep 2011 09:00:56 -0400 In-Reply-To: <20110905184524.GQ12086@tux1.beaverton.ibm.com> (Darrick J. Wong's message of "Mon, 5 Sep 2011 11:45:24 -0700") Sender: linux-ext4-owner@vger.kernel.org List-ID: >>>>> "Darrick" == Darrick J Wong writes: Darrick> I have some benchmarking data for various crc algorithms here: Darrick> https://ext4.wiki.kernel.org/index.php/Ext4_Metadata_Checksums#Benchmarking I've been meaning to update my own benchmark results from a few years ago but your table is much more comprehensive. Nice work! Darrick> Yes, the only downside to the slice-by-8 method is that it eats Darrick> 8K of data cache for the table. Not a huge issue on recent Darrick> Intel and POWER where the L1D is 32K, but I imagine it could be Darrick> painful elsewhere. I'll see if I can come up with something better for the DIF CRC. It's always calculated over either 512 or 4096-byte buffers. -- Martin K. Petersen Oracle Linux Engineering