From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] pktgen: nowait parameter. Date: Fri, 05 Sep 2014 14:26:18 -0700 (PDT) Message-ID: <20140905.142618.2240630803375505977.davem@davemloft.net> References: <87oauxibda.fsf@rustcorp.com.au> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, brouer@redhat.com, minipli@googlemail.com To: rusty@rustcorp.com.au Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:56243 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751955AbaIEV0V (ORCPT ); Fri, 5 Sep 2014 17:26:21 -0400 In-Reply-To: <87oauxibda.fsf@rustcorp.com.au> Sender: netdev-owner@vger.kernel.org List-ID: From: Rusty Russell Date: Wed, 03 Sep 2014 13:50:01 +0930 > While trying to measure speed of virtio_net, I was getting hangs. > This is because we skb_orphan() but delay the tx interrupt > indefinitely (by number of slots). > > With nowait, pktgen won't wait for the skb to be released. This > introduces an error, but it's ok if count >> ringsize. > > I updated the documentation, but it needs far more work (it > refers to pgset and an examples directory, none of which exist > in the kernel tree). > > Signed-off-by: Rusty Russell Please just make this a flag, like UDPCSUM, NO_TIMESTAMP, et al. Which also means that it should be capitalized. BTW, wrt. holding onto TX frames for unbounded amounts of time, I think this is a bad idea even with skb_orphan(). There are resources from the SKB you are hanging onto which can stall the removal of modules indefinitely, such as netfilter references.