From: Trond Myklebust Subject: Re: splice read byte accounting Date: Thu, 28 Jan 2010 10:15:34 -0500 Message-ID: <1264691734.7553.1.camel@localhost> References: <39A11474-A44E-49FE-8135-54B384254311@oracle.com> <1264634364.3788.177.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Linux NFS Mailing List To: Chuck Lever Return-path: Received: from mail-out1.uio.no ([129.240.10.57]:58437 "EHLO mail-out1.uio.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751828Ab0A1PPi (ORCPT ); Thu, 28 Jan 2010 10:15:38 -0500 In-Reply-To: Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, 2010-01-28 at 10:07 -0500, Chuck Lever wrote: > On Jan 27, 2010, at 6:19 PM, Trond Myklebust wrote: > > On Wed, 2010-01-27 at 17:22 -0500, Chuck Lever wrote: > >> Hi- > >> > >> nfs_file_splice_write() accounts for the bytes in the request in the > >> "normal bytes written" counter, but nfs_file_splice_read() does not > >> account for bytes read. > >> > >> Should the read path count these as normal bytes as well, or should > >> the write path not account for these bytes? > >> > > > > nfs_file_splice_read() should probably update NFSIOS_NORMALREADBYTES. > > > > That said, why do nfs_file_read(), nfs_file_write() and > > nfs_file_splice_write() update the stats with the requested number of > > bytes, irrespective of the number of bytes that were actually > > read/write? > > We're counting the number of bytes requested by applications. I'm not > sure which is more useful here; number of bytes requested, or number > of bytes actually read/written. For computing ratios of app bytes v. > otw bytes, I suppose the latter? > Yes. Most apps will just be inputting the buffer size as the 'number of bytes requested', which is not really a particularly useful number.