From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Rose Subject: Re: [RFC net-next 05/14] Fix intel/ixgbevf Date: Tue, 19 Jun 2012 11:07:04 -0700 Message-ID: <20120619110704.000045b2@unknown> References: <1340118848-30978-1-git-send-email-yuvalmin@broadcom.com> <1340118848-30978-6-git-send-email-yuvalmin@broadcom.com> <4FE09D3F.4060305@intel.com> <1340122013.2486.14.camel@lb-tlvb-eilong.il.broadcom.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Cc: Alexander Duyck , Yuval Mintz , , , Jeff Kirsher To: Return-path: Received: from mga11.intel.com ([192.55.52.93]:19826 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753030Ab2FSSHL (ORCPT ); Tue, 19 Jun 2012 14:07:11 -0400 In-Reply-To: <1340122013.2486.14.camel@lb-tlvb-eilong.il.broadcom.com> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 19 Jun 2012 19:06:53 +0300 Eilon Greenstein wrote: > On Tue, 2012-06-19 at 08:39 -0700, Alexander Duyck wrote: > > On 06/19/2012 08:13 AM, Yuval Mintz wrote: > > > Signed-off-by: Yuval Mintz > > > Signed-off-by: Eilon Greenstein > > > > > > Cc: Jeff Kirsher > > > --- > > > drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 5 +++-- > > > 1 files changed, 3 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c > > > b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c index > > > f69ec42..3ad46c2 100644 --- > > > a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c +++ > > > b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c @@ -2014,7 > > > +2014,7 @@ err_tx_ring_allocation: static int > > > ixgbevf_set_interrupt_capability(struct ixgbevf_adapter *adapter) > > > { int err = 0; > > > - int vector, v_budget; > > > + int vector, v_budget, ncpu; > > > > > > /* > > > * It's easy to be greedy for MSI-X vectors, but it > > > really @@ -2022,8 +2022,9 @@ static int > > > ixgbevf_set_interrupt_capability(struct ixgbevf_adapter *adapter) > > > * than CPU's. So let's be conservative and only ask for > > > * (roughly) twice the number of vectors as there are > > > CPU's. */ > > > + ncpu = min_t(int, num_online_cpus(), > > > DEFAULT_MAX_NUM_RSS_QUEUES); v_budget = > > > min(adapter->num_rx_queues + adapter->num_tx_queues, > > > - (int)(num_online_cpus() * 2)) + > > > NON_Q_VECTORS; > > > + ncpu * 2) + NON_Q_VECTORS; > > > > > > /* A failure in MSI-X entry allocation isn't fatal, but > > > it does > > > * mean we disable MSI-X capabilities of the adapter. */ > > This change is pointless on the ixgbevf driver. The VF hardware can > > support at most 4 RSS queues. As such num_rx_queues + num_tx_queues > > will never exceed 8 so you are essentially adding a necessary > > min(x,8). > > It is pointless with the current value, but if someone will edit the > kernel source code and replace the 8 with a 2, it will become > meaningful. The compiler will optimize this part, and I think that for > completion, it is best to keep this reference so a future default > number change will not be missed. > > Eilon I don't feel there is any real point to making this change to the ixgbevf driver. 82599 virtual functions have 3 MSI-X vectors, one of which is for the mailbox and the other two can be shared with tx/rx queue pairs or assigned separately to tx or rx queues. So this code is pointless no matter what value is set for DEFAULT_MAX_NUM_RSS_QUEUES. Perhaps the patches to the other drivers in your RFC will have some effect but this one looks like a no-op for the ixgbevf driver so there is no reason for it. - Greg > > > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html