From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [RFC] net: bump the default number of RSS queues Date: Tue, 3 Apr 2018 17:20:49 -0700 Message-ID: <3f6f40f3-cca2-0f43-8940-05003da88524@gmail.com> References: <20180404001422.6080-1-jakub.kicinski@netronome.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: brouer@redhat.com, alexander.duyck@gmail.com, oss-drivers@netronome.com To: Jakub Kicinski , davem@davemloft.net, netdev@vger.kernel.org Return-path: Received: from mail-pl0-f65.google.com ([209.85.160.65]:45223 "EHLO mail-pl0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756098AbeDDAUv (ORCPT ); Tue, 3 Apr 2018 20:20:51 -0400 Received: by mail-pl0-f65.google.com with SMTP id v18-v6so9485893ply.12 for ; Tue, 03 Apr 2018 17:20:50 -0700 (PDT) In-Reply-To: <20180404001422.6080-1-jakub.kicinski@netronome.com> Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: On 04/03/2018 05:14 PM, Jakub Kicinski wrote: > Some popular NIC vendors are not adhering to > netif_get_num_default_rss_queues() which leads to users being > surprised and filing bugs :) Bump the number of default RX > queues to something more reasonable for modern machines. > > Signed-off-by: Jakub Kicinski > --- > I'm mostly wondering what's the policy on this default? When > should it be applied? Why was 8 chosen as the default? We > can abandon using netif_get_num_default_rss_queues() for the > nfp but I wonder what's the correct course of action here... > Should new drivers use netif_get_num_default_rss_queues() for > example? > > include/linux/netdevice.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index 2a2d9cf50aa2..26fe145ada2a 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -3260,7 +3260,7 @@ static inline unsigned int get_netdev_rx_queue_index( > } > #endif > > -#define DEFAULT_MAX_NUM_RSS_QUEUES (8) > +#define DEFAULT_MAX_NUM_RSS_QUEUES (64) > int netif_get_num_default_rss_queues(void); There is no evidence having so many queues is beneficial. Too many queues -> lots of overhead in many cases. So I would rather not touch this, unless you can present good numbers ;)