From owner-freebsd-net@freebsd.org Fri Feb 28 19:52:21 2020 Return-Path: Delivered-To: freebsd-net@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 6E751243F74 for ; Fri, 28 Feb 2020 19:52:21 +0000 (UTC) (envelope-from slw@zxy.spb.ru) Received: from zxy.spb.ru (zxy.spb.ru [195.70.199.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 48TgDN1T1wz3MPF; Fri, 28 Feb 2020 19:52:20 +0000 (UTC) (envelope-from slw@zxy.spb.ru) Received: from slw by zxy.spb.ru with local (Exim 4.86 (FreeBSD)) (envelope-from ) id 1j7lgI-000MkQ-FK; Fri, 28 Feb 2020 22:52:18 +0300 Date: Fri, 28 Feb 2020 22:52:18 +0300 From: Slawa Olhovchenkov To: Vincenzo Maffione Cc: FreeBSD Net Subject: Re: Intel NETMAP performance and packet type Message-ID: <20200228195218.GS8012@zxy.spb.ru> References: <20200203204447.GD8028@zxy.spb.ru> <20200225150924.GM8012@zxy.spb.ru> <20200227201650.GO8012@zxy.spb.ru> <20200228112602.GP8012@zxy.spb.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: slw@zxy.spb.ru X-SA-Exim-Scanned: No (on zxy.spb.ru); SAEximRunCond expanded to false X-Rspamd-Queue-Id: 48TgDN1T1wz3MPF X-Spamd-Bar: + Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=none (mx1.freebsd.org: domain of slw@zxy.spb.ru has no SPF policy when checking 195.70.199.98) smtp.mailfrom=slw@zxy.spb.ru X-Spamd-Result: default: False [1.46 / 15.00]; ARC_NA(0.00)[]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-0.14)[-0.137,0]; MIME_GOOD(-0.10)[text/plain]; RCVD_TLS_LAST(0.00)[]; DMARC_NA(0.00)[zxy.spb.ru]; AUTH_NA(1.00)[]; NEURAL_SPAM_MEDIUM(0.62)[0.616,0]; IP_SCORE(0.08)[asn: 5495(0.38), country: RU(0.01)]; TO_DN_ALL(0.00)[]; RCPT_COUNT_TWO(0.00)[2]; R_SPF_NA(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:5495, ipnet:195.70.192.0/19, country:RU]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 28 Feb 2020 19:52:21 -0000 On Fri, Feb 28, 2020 at 06:37:22PM +0100, Vincenzo Maffione wrote: > Il giorno ven 28 feb 2020 alle ore 12:26 Slawa Olhovchenkov > ha scritto: > > > On Thu, Feb 27, 2020 at 11:16:50PM +0300, Slawa Olhovchenkov wrote: > > > > > On Thu, Feb 27, 2020 at 06:51:54PM +0100, Vincenzo Maffione wrote: > > > > > > > Hi, > > > > So, the issue is not the payload. > > > > If you look at the avg_batch statistics reported by pkt-gen, you'll see > > > > that in the ACK-flood experiment you have 4.92, whereas in the > > SYN-flood > > > > case you have 17.5. The batch is the number of packets (well, actually > > > > netmap descriptors, but in this case it's the same) that you receive > > (or > > > > transmit) for each poll() invocation. > > > > So in the first case you end up doing much more poll() calls, hence the > > > > higher per-packet overhead and the lower packet-rate. > > > > > > > > Why is the poll() called more frequently? That depends on packet > > timing and > > > > interrupt rate. There must be something different on your packet > > generator > > > > that produces this effect (e.g. different burstiness, or maybe the > > packet > > > > generator is not able to saturate the 10G link)? > > > > > > No, I am capture netstat output -- raw packet rate is the same. > > > Also, I am change card to chelsio T5 and don't see issuse. > > > > > > This is payload issuse, at driver level. > > > > > > > In any case, I would suggest measuring the RX interrupt rate, and check > > > > that it's higher in the ACK-flood case. Then you can try to lower the > > > > interrupt rate by tuning the interrupt moderation features of the > > Intel NIC > > > > (e,g. limit hw.ix.max_interrupt_rate and disable hw.ix.enable_aim or > > > > similar). > > > > By playing with the interrupt moderation you should be able to > > increase the > > > > avg_batch, and then increase throghput. > > > > > > Already limited. > > > > Also, is this normal (rxd_tail == rxd_head): > > > > dev.ix.0.queue0.rx_discarded: 0 > > dev.ix.0.queue0.rx_copies: 0 > > dev.ix.0.queue0.rx_bytes: 612041623304 > > dev.ix.0.queue0.rx_packets: 9563149414 > > dev.ix.0.queue0.rxd_tail: 1120 > > dev.ix.0.queue0.rxd_head: 1120 > > dev.ix.0.queue0.irqs: 40154885 > > dev.ix.0.queue0.interrupt_rate: 16129 > > dev.ix.0.queue0.tx_packets: 553897984 > > dev.ix.0.queue0.tso_tx: 0 > > dev.ix.0.queue0.txd_tail: 0 > > dev.ix.0.queue0.txd_head: 0 > > > > I am see this RX queue is stoped. > > Ah, may fault. This is different case on same Intel card, this is no ACK-flood. And I am see this on production traffic. > Yes, (rxd_tail == rxd_head) means that the NIC ran out of RX buffers. > rxd_head is the next descriptor that the NIC will use. rxd_tail is the next > descriptor that the driver will replenish. RX buffers are replenished by > the netmap NIOCRXSYNC routine, which is called on poll(). poll() still called frequenced but rxd_head/rxd_tail stalled. > However, rx_discarded is 0, which means that the NIC is not dropping > packets. So the problem should not be that poll() is not called frequently > enough. poll() called for all queue synchronously for multiple queue, stalled only one. > You should check rx_discarded for all the queues. All zero. > Another thing you need to check is how the load is balanced across the > receive queues. How many have you configured? Maybe the two workloads > (SYN-flood and ACK-flood) load different queues in different ways. Sorry, this is different case: after some time (after hour, for example) some queue stalled infinitly. Rest queue handle traffic. This is Intel card, iflib variant.