From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCHv5] virtio-spec: virtio network device RFS support Date: Thu, 6 Dec 2012 22:03:23 +0000 Message-ID: <1354831403.2828.63.camel@bwh-desktop.uk.solarflarecom.com> References: <20121203105843.GA26194@redhat.com> <1354739966.2655.25.camel@bwh-desktop.uk.solarflarecom.com> <20121206081320.GD10837@redhat.com> <1354824194.2828.6.camel@bwh-desktop.uk.solarflarecom.com> <20121206202921.GB4340@redhat.com> <1354827239.2828.36.camel@bwh-desktop.uk.solarflarecom.com> <20121206210132.GB6576@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Jason Wang , , , , To: "Michael S. Tsirkin" Return-path: Received: from webmail.solarflare.com ([12.187.104.25]:30066 "EHLO webmail.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932902Ab2LFWD2 (ORCPT ); Thu, 6 Dec 2012 17:03:28 -0500 In-Reply-To: <20121206210132.GB6576@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Thu, 2012-12-06 at 23:01 +0200, Michael S. Tsirkin wrote: > On Thu, Dec 06, 2012 at 08:53:59PM +0000, Ben Hutchings wrote: > > On Thu, 2012-12-06 at 22:29 +0200, Michael S. Tsirkin wrote: > > > On Thu, Dec 06, 2012 at 08:03:14PM +0000, Ben Hutchings wrote: > > [...] > > > > Since this doesn't seem to be intended to have *any* connection with the > > > > existing core networking feature called RFS, perhaps you could find a > > > > different name for it. > > > > > > > > Ben. > > > > > > > > > Ah I see what you mean. We started out calling this feature "multiqueue" > > > Rusty suggested "RFS" since it gives similar functionality to RFS but in > > > device: it has receive steering logic per flow as part of the device. > > > > The name is quite generic, but in the context of Linux it has so far > > been used for a specific software feature and not as a generic name for > > flow steering by hardware (or drivers). The existing documentation > > (Documentation/networking/scaling.txt) states quite clearly that 'RFS' > > means that specific software implementation (with optional driver > > integration) and configuration interface. > > > > > Maybe simply adding a statement similar to the one above would be > > > sufficient to avoid confusion? > > > > No, I don't think it's sufficient. We have documentation that says how > > to configure 'RFS', and you're proposing to add a very similar feature > > called 'RFS' that is configured differently. No matter how clearly you > > distinguish them in new documentation, this will make the old > > documentation confusing. > > > > Ben. > > I don't mind, renaming is just s/RFS/whatever/ away - > how should hardware call this in your opinion? If by 'this' you mean the use of perfect filters or a large hash table to select the RX queue per flow, then 'flow steering'. But that is usually combined with the fall-back of a simple mapping from hash to queue ('RSS' or 'flow hashing') in case there is no specific queue selection yet, which I can see tun has. And you're specifying multiple transmit queues too. If you want a name for the whole set of features involved, I don't see any better name than 'multiqueue'/'MQ'. If you want a name for this specific flow steering mechanism, add some distinguishing adjective(s) like 'virtual' or 'automatic'. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.