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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Eliezer Tamir <eliezer.tamir@linux.intel.com>
Cc: Eliezer Tamir <eliezer.tamir@linux.jf.intel.com>,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	Dave Miller <davem@davemloft.net>,
	Jesse Brandeburg <jesse.brandeburg@intel.com>,
	e1000-devel@lists.sourceforge.net,
	Willem de Bruijn <willemb@google.com>,
	Andi Kleen <andi@firstfloor.org>, HPA <hpa@zytor.com>,
	Eliezer Tamir <eliezer@tamir.org.il>
Subject: Re: [RFC PATCH 1/5] net: implement support for low latency socket polling
Date: Mon, 04 Mar 2013 08:15:59 -0800	[thread overview]
Message-ID: <1362413759.15793.98.camel@edumazet-glaptop> (raw)
In-Reply-To: <5134BD9B.2080003@linux.intel.com>

On Mon, 2013-03-04 at 17:28 +0200, Eliezer Tamir wrote:
> On 04/03/2013 16:52, Eric Dumazet wrote:
> > On Mon, 2013-03-04 at 10:43 +0200, Eliezer Tamir wrote:
> >
> >> One could for example increment the generation id every time the RTNL is
> >> taken. or is this too much?
> >
> > RTNL is taken for a lot of operations, it would be better to have a
> > finer grained increment.
> 
> If is taken rarely enough it will still be worth it.
> 

Yes, but eventually it makes attempts to get rid of RTNL a nightmare.

When adding new network features, just use the right semantic from the
beginning.

> Otherwise it may be hard to know what operations need to invalidate the 
> napi reference. It can very well be HW dependent, and then you end up 
> adding a function for drivers to call to do the invalidation.
> 
> Or we can decide that we only care about catastrophic events and only 
> worry about a napi completely going away and not worry about 
> configuration changes.(Polling the wrong queue will not kill you, it's 
> just a waste of perfectly good CPU cycles.)

As long as the incoming packets are able to update the information, who
cares if one packet missed the poll ?
 



  reply	other threads:[~2013-03-04 16:16 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-27 17:55 [RFC PATCH 0/5] net: low latency Ethernet device polling Eliezer Tamir
2013-02-27 17:55 ` [RFC PATCH 1/5] net: implement support for low latency socket polling Eliezer Tamir
2013-03-03 18:35   ` Eric Dumazet
2013-03-03 19:21     ` Andi Kleen
2013-03-03 21:20       ` Eric Dumazet
2013-03-04  3:55         ` Andi Kleen
2013-03-04  8:43     ` Eliezer Tamir
2013-03-04 14:52       ` Eric Dumazet
2013-03-04 15:28         ` Eliezer Tamir
2013-03-04 16:15           ` Eric Dumazet [this message]
2013-03-04  7:23   ` Cong Wang
2013-03-05 16:43   ` Ben Hutchings
2013-03-05 17:15     ` Eliezer Tamir
2013-03-05 19:57       ` David Miller
2013-03-05 19:55     ` David Miller
2013-03-05 20:03       ` H. Peter Anvin
2013-02-27 17:56 ` [RFC PATCH 2/5] tcp: add TCP support for low latency receive poll Eliezer Tamir
2013-03-05 17:13   ` Ben Hutchings
2013-02-27 17:56 ` [RFC PATCH 3/5] ixgbe: Add support for ndo_ll_poll Eliezer Tamir
2013-02-27 18:41   ` Eric Dumazet
2013-02-27 19:20     ` Eliezer Tamir
2013-03-05 17:26   ` Ben Hutchings
2013-03-05 17:28     ` Ben Hutchings
2013-03-05 17:36       ` Eric Dumazet
2013-02-27 17:56 ` [RFC PATCH 4/5] ixgbe: add extra stats " Eliezer Tamir
2013-02-27 17:56 ` [RFC PATCH 5/5] ixgbe: kprobes latency test module Eliezer Tamir
2013-02-27 18:07 ` [RFC PATCH 0/5] net: low latency Ethernet device polling Eliezer Tamir
2013-02-27 18:13 ` Stephen Hemminger
2013-02-27 18:47   ` Tom Herbert
2013-02-27 19:17     ` Eliezer Tamir
2013-03-04 22:34       ` Ben Hutchings
2013-02-27 19:58 ` Rick Jones
2013-02-27 20:40   ` Eliezer Tamir
2013-02-27 21:42     ` Ben Greear
2013-02-28  8:38       ` Eliezer Tamir
2013-03-01 21:24 ` David Miller
2013-03-01 22:57   ` Tom Herbert
2013-03-02 17:02   ` Eliezer Tamir
2013-03-04  7:37 ` Cong Wang
2013-03-04  8:19   ` Eliezer Tamir
2013-03-04  8:46     ` Eliezer Tamir
2013-03-04 17:19 ` Stephen Hemminger

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