From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: Re: [PATCH v3 net-next] pktgen: introduce 'rx' mode Date: Sat, 2 May 2015 18:46:25 +0200 Message-ID: <20150502184625.25426091@redhat.com> References: <1430457130-16003-1-git-send-email-ast@plumgrid.com> <20150502104621.4fede885@redhat.com> <5544F4D7.50202@plumgrid.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: brouer@redhat.com, "David S. Miller" , Eric Dumazet , netdev@vger.kernel.org, Robert Olsson , Ben Greear To: Alexei Starovoitov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:50161 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750966AbbEBQql (ORCPT ); Sat, 2 May 2015 12:46:41 -0400 In-Reply-To: <5544F4D7.50202@plumgrid.com> Sender: netdev-owner@vger.kernel.org List-ID: On Sat, 02 May 2015 09:01:27 -0700 Alexei Starovoitov wrote: > On 5/2/15 1:46 AM, Jesper Dangaard Brouer wrote: > > On Thu, 30 Apr 2015 22:12:10 -0700 > > Alexei Starovoitov wrote: > > > >> Introduce 'RX' mode for pktgen which generates the packets > >> using familiar pktgen commands, but feeds them into > >> netif_receive_skb() instead of ndo_start_xmit(). > >> > >> It is designed to test netif_receive_skb and ingress qdisc > >> performace only. Make sure to understand how it works before > >> using it for other rx benchmarking. > > > > Hi Alexei > > > > First of all I love the idea of modifying pktgen to performance test > > the RX path. > > > > I'm not sure the simple "rx" flag is a good "name". It likely > > conflicts with other work where pktgen can receive it own packets, e.g. > > https://people.kth.se/~danieltt/pktgen/ or Ben Greer's solution. > > > > In your patch several things are not pktgen "compliant": > > 1. Flags in pktgen are normally in upper-case "RX" > > 2. Flags also require a disable "!RX" option > > 3. You didn't add the flag to list of supported flags > > 4. You don't output if the flag is enabled > > 5. You didn't update the documentation (Documentation/networking/pktgen.txt) > > It's actually not a flag, because it cannot be disabled by design. > It cannot be flipped back and forth, because it affects what other > real flags can be applied. It's a _mode_. > I don't see yet how I can safely switch this mode back into tx while > things are running. It would need a whole new mechanism of stopping > things and so on. I wanted to start simple. > For 5, yeah, agree, need to update the doc. > As far as name, I don't have preferences. Will 'stack_inject' sound > better? I can respin with that name if you like, but disabling it on > the fly is a major change. I'd rather do it in small steps. Okay, I guess it makes sense as a "mode". Calling it "stack_inject" is fairly descriptive, but I also like Daniel's idea of option "xmit_mode [rx|tx]". I would not allow it to be reconfigured on the fly, but only when the test/thread is stopped (!pkt_dev->running), allow re-configuring back to "TX" mode. Although, removing (and free) the entire pkt_dev, would implicitly reset it back. -- Best regards, Jesper Dangaard Brouer MSc.CS, Sr. Network Kernel Developer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer