From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: RE: [RFC net-next (v2) 11/14] igb: set maximal number of default RSS queues Date: Mon, 25 Jun 2012 19:38:18 +0100 Message-ID: <1340649498.2572.11.camel@bwh-desktop.uk.solarflarecom.com> References: <1340624745-8650-1-git-send-email-yuvalmin@broadcom.com> <1340624745-8650-12-git-send-email-yuvalmin@broadcom.com> <06DFBC1E25D8024DB214DC7F41A3CD3448870CE4@ORSMSX101.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Yuval Mintz , "davem@davemloft.net" , "netdev@vger.kernel.org" , "eilong@broadcom.com" , "Kirsher, Jeffrey T" To: "Vick, Matthew" Return-path: Received: from webmail.solarflare.com ([12.187.104.25]:29039 "EHLO ocex02.SolarFlarecom.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756127Ab2FYSiX (ORCPT ); Mon, 25 Jun 2012 14:38:23 -0400 In-Reply-To: <06DFBC1E25D8024DB214DC7F41A3CD3448870CE4@ORSMSX101.amr.corp.intel.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 2012-06-25 at 17:31 +0000, Vick, Matthew wrote: > > -----Original Message----- > > From: netdev-owner@vger.kernel.org [mailto:netdev- > > owner@vger.kernel.org] On Behalf Of Yuval Mintz > > Sent: Monday, June 25, 2012 4:46 AM > > To: davem@davemloft.net; netdev@vger.kernel.org > > Cc: eilong@broadcom.com; Yuval Mintz; Kirsher, Jeffrey T > > Subject: [RFC net-next (v2) 11/14] igb: set maximal number of default > > RSS queues > > > > Signed-off-by: Yuval Mintz > > Signed-off-by: Eilon Greenstein > > > > Cc: Jeff Kirsher > > --- > > drivers/net/ethernet/intel/igb/igb_main.c | 3 ++- > > 1 files changed, 2 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/net/ethernet/intel/igb/igb_main.c > > b/drivers/net/ethernet/intel/igb/igb_main.c > > index 01ced68..b11ee60 100644 > > --- a/drivers/net/ethernet/intel/igb/igb_main.c > > +++ b/drivers/net/ethernet/intel/igb/igb_main.c > > @@ -2465,7 +2465,8 @@ static int __devinit igb_sw_init(struct > > igb_adapter *adapter) > > break; > > } > > > > - adapter->rss_queues = min_t(u32, max_rss_queues, > > num_online_cpus()); > > + adapter->rss_queues = min_t(u32, max_rss_queues, > > + netif_get_num_default_rss_queues()); > > > > /* Determine if we need to pair queues. */ > > switch (hw->mac.type) { > > -- > > 1.7.9.rc2 > > Since igb supports a maximum of 8 RSS queues anyway, it's generally > unaffected by this change. I'm interested in providing a global configuration mechanism for this, which is why I asked Yuval to introduce this function. > That being said, I'm confused about what you're trying to > accomplish--is it to standardize the number of RSS queues or limit the > number of interrupts by default? Or is it the former with a hope that > it will trickle down to the latter? > > For example, if you take an igb device that supports 8 RSS queues > (say, I350) and you change the default to 4 RSS queues, you will end > up with the same number of interrupt vectors being requested as we > will disable queue pairing and request separate vectors for Rx/Tx > queues. I haven't looked at the other drivers affected by this RFC, > but it's possible other drivers behave the same way. sfc also supports those two modes, but under control of a module parameter. If it's a common enough feature then perhaps it should also be subject to global configuration (though that might be confusing if most drivers continue to support only one mode). 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.