From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from s3.sipsolutions.net ([144.76.43.152]:42225 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754725Ab3EaSlp (ORCPT ); Fri, 31 May 2013 14:41:45 -0400 Message-ID: <1370025698.14117.15.camel@jlt4.sipsolutions.net> (sfid-20130531_204153_665019_C0E78175) Subject: Re: Another try at getting pktgen to work with wifi. From: Johannes Berg To: Ben Greear Cc: Felix Fietkau , "linux-wireless@vger.kernel.org" , netdev Date: Fri, 31 May 2013 20:41:38 +0200 In-Reply-To: <51A8E53E.8030101@candelatech.com> References: <51A79E4A.7000609@candelatech.com> <51A7B049.9090201@openwrt.org> <51A7BA63.4080403@candelatech.com> <51A857BF.7070008@openwrt.org> <51A8DC1C.1040908@candelatech.com> (sfid-20130531_192143_291284_FB196B0A) <1370021846.14117.13.camel@jlt4.sipsolutions.net> <51A8E53E.8030101@candelatech.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Fri, 2013-05-31 at 11:00 -0700, Ben Greear wrote: > I think it might be more that the wifi stacks have some specific > assumptions about how skb->priority maps to queues and QoS. If > they get out of sync, then the TID mappings and so forth get > confused. What I'm saying though is that I don't see where skb->priority is even _used_ in the wifi stack. I can see it getting set, but not used. > I actually don't know exactly why pktgen shows this problem, > but it must be because it does direct calls to the hard_start_xmit > method of the netdev when (most?) other paths do dev_queue_xmit > or similar. Other paths go through select_queue(), obviously. > > Actually that makes it seem like something else should be doing packet > > classification, not mac80211 in select_queue()? > > > > Where is skb->priority actually really used in mac80211? I don't see > > much? > > There's a bit more in net/wireless/util.c, at least (cfg80211_classify8021d, for instance). But that's pretty much all assignments. > The mac80211/wme.c uses it. Some of this is called from the drivers > (line 1916 or so of ath9k/xmit.c). What's called there? I don't see any reason for that to use skb->priority? > It's all a bit convoluted in my opinion, but there may well > be good reasons for it. More likely legacy. johannes From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Berg Subject: Re: Another try at getting pktgen to work with wifi. Date: Fri, 31 May 2013 20:41:38 +0200 Message-ID: <1370025698.14117.15.camel@jlt4.sipsolutions.net> References: <51A79E4A.7000609@candelatech.com> <51A7B049.9090201@openwrt.org> <51A7BA63.4080403@candelatech.com> <51A857BF.7070008@openwrt.org> <51A8DC1C.1040908@candelatech.com> (sfid-20130531_192143_291284_FB196B0A) <1370021846.14117.13.camel@jlt4.sipsolutions.net> <51A8E53E.8030101@candelatech.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Felix Fietkau , "linux-wireless-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , netdev To: Ben Greear Return-path: In-Reply-To: <51A8E53E.8030101-my8/4N5VtI7c+919tysfdA@public.gmane.org> Sender: linux-wireless-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On Fri, 2013-05-31 at 11:00 -0700, Ben Greear wrote: > I think it might be more that the wifi stacks have some specific > assumptions about how skb->priority maps to queues and QoS. If > they get out of sync, then the TID mappings and so forth get > confused. What I'm saying though is that I don't see where skb->priority is even _used_ in the wifi stack. I can see it getting set, but not used. > I actually don't know exactly why pktgen shows this problem, > but it must be because it does direct calls to the hard_start_xmit > method of the netdev when (most?) other paths do dev_queue_xmit > or similar. Other paths go through select_queue(), obviously. > > Actually that makes it seem like something else should be doing packet > > classification, not mac80211 in select_queue()? > > > > Where is skb->priority actually really used in mac80211? I don't see > > much? > > There's a bit more in net/wireless/util.c, at least (cfg80211_classify8021d, for instance). But that's pretty much all assignments. > The mac80211/wme.c uses it. Some of this is called from the drivers > (line 1916 or so of ath9k/xmit.c). What's called there? I don't see any reason for that to use skb->priority? > It's all a bit convoluted in my opinion, but there may well > be good reasons for it. More likely legacy. johannes -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html