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Message-ID: <20170815115756.7ef50c23@redhat.com>
Date: Tue, 15 Aug 2017 11:57:56 +0200
From: Jesper Dangaard Brouer <brouer@...hat.com>
To: Paweł Staszewski <pstaszewski@...are.pl>
Cc: Linux Kernel Network Developers <netdev@...r.kernel.org>,
Alexander Duyck <alexander.duyck@...il.com>,
Saeed Mahameed <saeedm@...lanox.com>,
Tariq Toukan <tariqt@...lanox.com>, brouer@...hat.com
Subject: Re: Kernel 4.13.0-rc4-next-20170811 - IP Routing / Forwarding
performance vs Core/RSS number / HT on
On Tue, 15 Aug 2017 11:30:43 +0200 Paweł Staszewski <pstaszewski@...are.pl> wrote:
> W dniu 2017-08-15 o 11:23, Jesper Dangaard Brouer pisze:
> > On Tue, 15 Aug 2017 02:38:56 +0200
> > Paweł Staszewski <pstaszewski@...are.pl> wrote:
> >
> >> W dniu 2017-08-14 o 18:19, Jesper Dangaard Brouer pisze:
> >>> On Sun, 13 Aug 2017 18:58:58 +0200 Paweł Staszewski <pstaszewski@...are.pl> wrote:
> >>>
> >>>> To show some difference below comparision vlan/no-vlan traffic
> >>>>
> >>>> 10Mpps forwarded traffic vith no-vlan vs 6.9Mpps with vlan
> >>> I'm trying to reproduce in my testlab (with ixgbe). I do see, a
> >>> performance reduction of about 10-19% when I forward out a VLAN
> >>> interface. This is larger than I expected, but still lower than what
> >>> you reported 30-40% slowdown.
> >>>
> >>> [...]
> >> Ok mellanox afrrived (MT27700 - mlnx5 driver)
> >> And to compare melannox with vlans and without: 33% performance
> >> degradation (less than with ixgbe where i reach ~40% with same settings)
> >>
> >> Mellanox without TX traffix on vlan:
> >> ID;CPU_CORES / RSS QUEUES;PKT_SIZE;PPS_RX;BPS_RX;PPS_TX;BPS_TX
> >> 0;16;64;11089305;709715520;8871553;567779392
> >> 1;16;64;11096292;710162688;11095566;710116224
> >> 2;16;64;11095770;710129280;11096799;710195136
> >> 3;16;64;11097199;710220736;11097702;710252928
> >> 4;16;64;11080984;567081856;11079662;709098368
> >> 5;16;64;11077696;708972544;11077039;708930496
> >> 6;16;64;11082991;709311424;8864802;567347328
> >> 7;16;64;11089596;709734144;8870927;709789184
> >> 8;16;64;11094043;710018752;11095391;710105024
> >>
> >> Mellanox with TX traffic on vlan:
> >> ID;CPU_CORES / RSS QUEUES;PKT_SIZE;PPS_RX;BPS_RX;PPS_TX;BPS_TX
> >> 0;16;64;7369914;471674496;7370281;471697980
> >> 1;16;64;7368896;471609408;7368043;471554752
> >> 2;16;64;7367577;471524864;7367759;471536576
> >> 3;16;64;7368744;377305344;7369391;471641024
> >> 4;16;64;7366824;471476736;7364330;471237120
> >> 5;16;64;7368352;471574528;7367239;471503296
> >> 6;16;64;7367459;471517376;7367806;471539584
> >> 7;16;64;7367190;471500160;7367988;471551232
> >> 8;16;64;7368023;471553472;7368076;471556864
> > I wonder if the drivers page recycler is active/working or not, and if
> > the situation is different between VLAN vs no-vlan (given
> > page_frag_free is so high in you perf top). The Mellanox drivers
> > fortunately have a stats counter to tell us this explicitly (which the
> > ixgbe driver doesn't).
> >
> > You can use my ethtool_stats.pl script watch these stats:
> > https://github.com/netoptimizer/network-testing/blob/master/bin/ethtool_stats.pl
> > (Hint perl dependency: dnf install perl-Time-HiRes)
> For RX NIC:
> Show adapter(s) (enp175s0f0) statistics (ONLY that changed!)
> Ethtool(enp175s0f0) stat: 78380071 ( 78,380,071) <= rx0_bytes /sec
> Ethtool(enp175s0f0) stat: 230978 ( 230,978) <= rx0_cache_reuse /sec
> Ethtool(enp175s0f0) stat: 1152648 ( 1,152,648) <= rx0_csum_complete /sec
> Ethtool(enp175s0f0) stat: 1152648 ( 1,152,648) <= rx0_packets /sec
> Ethtool(enp175s0f0) stat: 921614 ( 921,614) <= rx0_page_reuse /sec
> Ethtool(enp175s0f0) stat: 78956591 ( 78,956,591) <= rx1_bytes /sec
> Ethtool(enp175s0f0) stat: 233343 ( 233,343) <= rx1_cache_reuse /sec
> Ethtool(enp175s0f0) stat: 1161126 ( 1,161,126) <= rx1_csum_complete /sec
> Ethtool(enp175s0f0) stat: 1161126 ( 1,161,126) <= rx1_packets /sec
> Ethtool(enp175s0f0) stat: 927793 ( 927,793) <= rx1_page_reuse /sec
> Ethtool(enp175s0f0) stat: 79677124 ( 79,677,124) <= rx2_bytes /sec
> Ethtool(enp175s0f0) stat: 233735 ( 233,735) <= rx2_cache_reuse /sec
> Ethtool(enp175s0f0) stat: 1171722 ( 1,171,722) <= rx2_csum_complete /sec
> Ethtool(enp175s0f0) stat: 1171722 ( 1,171,722) <= rx2_packets /sec
> Ethtool(enp175s0f0) stat: 937989 ( 937,989) <= rx2_page_reuse /sec
> Ethtool(enp175s0f0) stat: 78392893 ( 78,392,893) <= rx3_bytes /sec
> Ethtool(enp175s0f0) stat: 230311 ( 230,311) <= rx3_cache_reuse /sec
> Ethtool(enp175s0f0) stat: 1152837 ( 1,152,837) <= rx3_csum_complete /sec
> Ethtool(enp175s0f0) stat: 1152837 ( 1,152,837) <= rx3_packets /sec
> Ethtool(enp175s0f0) stat: 922513 ( 922,513) <= rx3_page_reuse /sec
> Ethtool(enp175s0f0) stat: 65165583 ( 65,165,583) <= rx4_bytes /sec
> Ethtool(enp175s0f0) stat: 191969 ( 191,969) <= rx4_cache_reuse /sec
> Ethtool(enp175s0f0) stat: 958317 ( 958,317) <= rx4_csum_complete /sec
> Ethtool(enp175s0f0) stat: 958317 ( 958,317) <= rx4_packets /sec
> Ethtool(enp175s0f0) stat: 766332 ( 766,332) <= rx4_page_reuse /sec
> Ethtool(enp175s0f0) stat: 66920721 ( 66,920,721) <= rx5_bytes /sec
> Ethtool(enp175s0f0) stat: 197150 ( 197,150) <= rx5_cache_reuse /sec
> Ethtool(enp175s0f0) stat: 984128 ( 984,128) <= rx5_csum_complete /sec
> Ethtool(enp175s0f0) stat: 984128 ( 984,128) <= rx5_packets /sec
> Ethtool(enp175s0f0) stat: 786978 ( 786,978) <= rx5_page_reuse /sec
> Ethtool(enp175s0f0) stat: 79076984 ( 79,076,984) <= rx6_bytes /sec
> Ethtool(enp175s0f0) stat: 233735 ( 233,735) <= rx6_cache_reuse /sec
> Ethtool(enp175s0f0) stat: 1162897 ( 1,162,897) <= rx6_csum_complete /sec
> Ethtool(enp175s0f0) stat: 1162897 ( 1,162,897) <= rx6_packets /sec
> Ethtool(enp175s0f0) stat: 929163 ( 929,163) <= rx6_page_reuse /sec
> Ethtool(enp175s0f0) stat: 78660672 ( 78,660,672) <= rx7_bytes /sec
> Ethtool(enp175s0f0) stat: 230413 ( 230,413) <= rx7_cache_reuse /sec
> Ethtool(enp175s0f0) stat: 1156775 ( 1,156,775) <= rx7_csum_complete /sec
> Ethtool(enp175s0f0) stat: 1156775 ( 1,156,775) <= rx7_packets /sec
> Ethtool(enp175s0f0) stat: 926376 ( 926,376) <= rx7_page_reuse /sec
> Ethtool(enp175s0f0) stat: 10674565 ( 10,674,565) <= rx_65_to_127_bytes_phy /sec
> Ethtool(enp175s0f0) stat: 605241031 ( 605,241,031) <= rx_bytes /sec
> Ethtool(enp175s0f0) stat: 768585608 ( 768,585,608) <= rx_bytes_phy /sec
> Ethtool(enp175s0f0) stat: 1781569 ( 1,781,569) <= rx_cache_reuse /sec
> Ethtool(enp175s0f0) stat: 8900603 ( 8,900,603) <= rx_csum_complete /sec
> Ethtool(enp175s0f0) stat: 1773785 ( 1,773,785) <= rx_out_of_buffer /sec
> Ethtool(enp175s0f0) stat: 8900603 ( 8,900,603) <= rx_packets /sec
> Ethtool(enp175s0f0) stat: 10674799 ( 10,674,799) <= rx_packets_phy /sec
> Ethtool(enp175s0f0) stat: 7118993 ( 7,118,993) <= rx_page_reuse /sec
> Ethtool(enp175s0f0) stat: 768565744 ( 768,565,744) <= rx_prio0_bytes /sec
> Ethtool(enp175s0f0) stat: 10674522 ( 10,674,522) <= rx_prio0_packets /sec
> Ethtool(enp175s0f0) stat: 725871089 ( 725,871,089) <= rx_vport_unicast_bytes /sec
> Ethtool(enp175s0f0) stat: 10674575 ( 10,674,575) <= rx_vport_unicast_packets /sec
It looks like the mlx5 page recycle mechanism works:
230413 ( 230,413) <= rx7_cache_reuse /sec
+ 926376 ( 926,376) <= rx7_page_reuse /sec
=1156789 (230413+926376)
-1156775 ( 1,156,775) <= rx7_packets /sec
= 14
You can also determine this as there are no counters for:
rx_cache_full or
rx_cache_empty or
rx1_cache_empty
rx1_cache_busy
> For TX nic with vlan:
> Show adapter(s) (enp175s0f1) statistics (ONLY that changed!)
> Ethtool(enp175s0f1) stat: 1 ( 1) <= rx_65_to_127_bytes_phy /sec
> Ethtool(enp175s0f1) stat: 71 ( 71) <= rx_bytes_phy /sec
> Ethtool(enp175s0f1) stat: 1 ( 1) <= rx_multicast_phy /sec
> Ethtool(enp175s0f1) stat: 1 ( 1) <= rx_packets_phy /sec
> Ethtool(enp175s0f1) stat: 71 ( 71) <= rx_prio0_bytes /sec
> Ethtool(enp175s0f1) stat: 1 ( 1) <= rx_prio0_packets /sec
> Ethtool(enp175s0f1) stat: 67 ( 67) <= rx_vport_multicast_bytes /sec
> Ethtool(enp175s0f1) stat: 1 ( 1) <= rx_vport_multicast_packets /sec
> Ethtool(enp175s0f1) stat: 64955114 ( 64,955,114) <= tx0_bytes /sec
> Ethtool(enp175s0f1) stat: 955222 ( 955,222) <= tx0_csum_none /sec
> Ethtool(enp175s0f1) stat: 26489 ( 26,489) <= tx0_nop /sec
> Ethtool(enp175s0f1) stat: 955222 ( 955,222) <= tx0_packets /sec
> Ethtool(enp175s0f1) stat: 66799214 ( 66,799,214) <= tx1_bytes /sec
> Ethtool(enp175s0f1) stat: 982341 ( 982,341) <= tx1_csum_none /sec
> Ethtool(enp175s0f1) stat: 27225 ( 27,225) <= tx1_nop /sec
> Ethtool(enp175s0f1) stat: 982341 ( 982,341) <= tx1_packets /sec
> Ethtool(enp175s0f1) stat: 78650421 ( 78,650,421) <= tx2_bytes /sec
> Ethtool(enp175s0f1) stat: 1156624 ( 1,156,624) <= tx2_csum_none /sec
> Ethtool(enp175s0f1) stat: 32059 ( 32,059) <= tx2_nop /sec
> Ethtool(enp175s0f1) stat: 1156624 ( 1,156,624) <= tx2_packets /sec
> Ethtool(enp175s0f1) stat: 78186849 ( 78,186,849) <= tx3_bytes /sec
> Ethtool(enp175s0f1) stat: 1149807 ( 1,149,807) <= tx3_csum_none /sec
> Ethtool(enp175s0f1) stat: 31879 ( 31,879) <= tx3_nop /sec
> Ethtool(enp175s0f1) stat: 1149807 ( 1,149,807) <= tx3_packets /sec
> Ethtool(enp175s0f1) stat: 234 ( 234) <= tx3_xmit_more /sec
> Ethtool(enp175s0f1) stat: 78466099 ( 78,466,099) <= tx4_bytes /sec
> Ethtool(enp175s0f1) stat: 1153913 ( 1,153,913) <= tx4_csum_none /sec
> Ethtool(enp175s0f1) stat: 31990 ( 31,990) <= tx4_nop /sec
> Ethtool(enp175s0f1) stat: 1153913 ( 1,153,913) <= tx4_packets /sec
> Ethtool(enp175s0f1) stat: 78765724 ( 78,765,724) <= tx5_bytes /sec
> Ethtool(enp175s0f1) stat: 1158319 ( 1,158,319) <= tx5_csum_none /sec
> Ethtool(enp175s0f1) stat: 32115 ( 32,115) <= tx5_nop /sec
> Ethtool(enp175s0f1) stat: 1158319 ( 1,158,319) <= tx5_packets /sec
> Ethtool(enp175s0f1) stat: 264 ( 264) <= tx5_xmit_more /sec
> Ethtool(enp175s0f1) stat: 79669524 ( 79,669,524) <= tx6_bytes /sec
> Ethtool(enp175s0f1) stat: 1171611 ( 1,171,611) <= tx6_csum_none /sec
> Ethtool(enp175s0f1) stat: 32490 ( 32,490) <= tx6_nop /sec
> Ethtool(enp175s0f1) stat: 1171611 ( 1,171,611) <= tx6_packets /sec
> Ethtool(enp175s0f1) stat: 79389329 ( 79,389,329) <= tx7_bytes /sec
> Ethtool(enp175s0f1) stat: 1167490 ( 1,167,490) <= tx7_csum_none /sec
> Ethtool(enp175s0f1) stat: 32365 ( 32,365) <= tx7_nop /sec
> Ethtool(enp175s0f1) stat: 1167490 ( 1,167,490) <= tx7_packets /sec
> Ethtool(enp175s0f1) stat: 604885175 ( 604,885,175) <= tx_bytes /sec
> Ethtool(enp175s0f1) stat: 676059749 ( 676,059,749) <= tx_bytes_phy /sec
> Ethtool(enp175s0f1) stat: 8895370 ( 8,895,370) <= tx_packets /sec
> Ethtool(enp175s0f1) stat: 8895522 ( 8,895,522) <= tx_packets_phy /sec
> Ethtool(enp175s0f1) stat: 676063067 ( 676,063,067) <= tx_prio0_bytes /sec
> Ethtool(enp175s0f1) stat: 8895566 ( 8,895,566) <= tx_prio0_packets /sec
> Ethtool(enp175s0f1) stat: 640470657 ( 640,470,657) <= tx_vport_unicast_bytes /sec
> Ethtool(enp175s0f1) stat: 8895427 ( 8,895,427) <= tx_vport_unicast_packets /sec
> Ethtool(enp175s0f1) stat: 498 ( 498) <= tx_xmit_more /sec
We are seeing some xmit_more, this is interesting. Have you noticed,
if (in the VLAN case) there is a queue in the qdisc layer?
Simply inspect with: tc -s qdisc show dev ixgbe2
> >
> >> ethtool settings for both tests:
> >> ifc='enp175s0f0 enp175s0f1'
> >> for i in $ifc
> >> do
> >> ip link set up dev $i
> >> ethtool -A $i autoneg off rx off tx off
> >> ethtool -G $i rx 128 tx 256
> > The ring queue size recommendations, might be different for the mlx5
> > driver (Cc'ing Mellanox maintainers).
> >
> >
> >> ip link set $i txqueuelen 1000
> >> ethtool -C $i rx-usecs 25
> >> ethtool -L $i combined 16
> >> ethtool -K $i gro off tso off gso off sg on l2-fwd-offload off
> >> tx-nocache-copy off ntuple on
> >> ethtool -N $i rx-flow-hash udp4 sdfn
> >> done
> > Thanks for being explicit about what you setup is :-)
> >
> >> and perf top:
> >> PerfTop: 83650 irqs/sec kernel:99.7% exact: 0.0% [4000Hz
> >> cycles], (all, 56 CPUs)
> >> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> >>
> >> 14.25% [kernel] [k] dst_release
> >> 14.17% [kernel] [k] skb_dst_force
> >> 13.41% [kernel] [k] rt_cache_valid
> >> 11.47% [kernel] [k] ip_finish_output2
> >> 7.01% [kernel] [k] do_raw_spin_lock
> >> 5.07% [kernel] [k] page_frag_free
> >> 3.47% [mlx5_core] [k] mlx5e_xmit
> >> 2.88% [kernel] [k] fib_table_lookup
> >> 2.43% [mlx5_core] [k] skb_from_cqe.isra.32
> >> 1.97% [kernel] [k] virt_to_head_page
> >> 1.81% [mlx5_core] [k] mlx5e_poll_tx_cq
> >> 0.93% [kernel] [k] __dev_queue_xmit
> >> 0.87% [kernel] [k] __build_skb
> >> 0.84% [kernel] [k] ipt_do_table
> >> 0.79% [kernel] [k] ip_rcv
> >> 0.79% [kernel] [k] acpi_processor_ffh_cstate_enter
> >> 0.78% [kernel] [k] netif_skb_features
> >> 0.73% [kernel] [k] __netif_receive_skb_core
> >> 0.52% [kernel] [k] dev_hard_start_xmit
> >> 0.52% [kernel] [k] build_skb
> >> 0.51% [kernel] [k] ip_route_input_rcu
> >> 0.50% [kernel] [k] skb_unref
> >> 0.49% [kernel] [k] ip_forward
> >> 0.48% [mlx5_core] [k] mlx5_cqwq_get_cqe
> >> 0.44% [kernel] [k] udp_v4_early_demux
> >> 0.41% [kernel] [k] napi_consume_skb
> >> 0.40% [kernel] [k] __local_bh_enable_ip
> >> 0.39% [kernel] [k] ip_rcv_finish
> >> 0.39% [kernel] [k] kmem_cache_alloc
> >> 0.38% [kernel] [k] sch_direct_xmit
> >> 0.33% [kernel] [k] validate_xmit_skb
> >> 0.32% [mlx5_core] [k] mlx5e_free_rx_wqe_reuse
> >> 0.29% [kernel] [k] netdev_pick_tx
> >> 0.28% [mlx5_core] [k] mlx5e_build_rx_skb
> >> 0.27% [kernel] [k] deliver_ptype_list_skb
> >> 0.26% [kernel] [k] fib_validate_source
> >> 0.26% [mlx5_core] [k] mlx5e_napi_poll
> >> 0.26% [mlx5_core] [k] mlx5e_handle_rx_cqe
> >> 0.26% [mlx5_core] [k] mlx5e_rx_cache_get
> >> 0.25% [kernel] [k] eth_header
> >> 0.23% [kernel] [k] skb_network_protocol
> >> 0.20% [kernel] [k] nf_hook_slow
> >> 0.20% [kernel] [k] vlan_passthru_hard_header
> >> 0.20% [kernel] [k] vlan_dev_hard_start_xmit
> >> 0.19% [kernel] [k] swiotlb_map_page
> >> 0.18% [kernel] [k] compound_head
> >> 0.18% [kernel] [k] neigh_connected_output
> >> 0.18% [mlx5_core] [k] mlx5e_alloc_rx_wqe
> >> 0.18% [kernel] [k] ip_output
> >> 0.17% [kernel] [k] prefetch_freepointer.isra.70
> >> 0.17% [kernel] [k] __slab_free
> >> 0.16% [kernel] [k] eth_type_vlan
> >> 0.16% [kernel] [k] ip_finish_output
> >> 0.15% [kernel] [k] kmem_cache_free_bulk
> >> 0.14% [kernel] [k] netif_receive_skb_internal
> >>
> >>
> >>
> >>
> >> wondering why this:
> >> 1.97% [kernel] [k] virt_to_head_page
> >> is in top...
> > This is related to the page_frag_free() call, but it is weird that it
> > shows up because it is suppose to be inlined (it is explicitly marked
> > inline in include/linux/mm.h).
> >
> >
> >>>>>>> perf top:
> >>>>>>>
> >>>>>>> PerfTop: 77835 irqs/sec kernel:99.7%
> >>>>>>> ---------------------------------------------
> >>>>>>>
> >>>>>>> 16.32% [kernel] [k] skb_dst_force
> >>>>>>> 16.30% [kernel] [k] dst_release
> >>>>>>> 15.11% [kernel] [k] rt_cache_valid
> >>>>>>> 12.62% [kernel] [k] ipv4_mtu
> >>>>>> It seems a little strange that these 4 functions are on the top
> >>> I don't see these in my test.
> >>>
> >>>>>>
> >>>>>>> 5.60% [kernel] [k] do_raw_spin_lock
> >>>>>> Why is calling/taking this lock? (Use perf call-graph recording).
> >>>>> can be hard to paste it here:)
> >>>>> attached file
> >>> The attached was very big. Please don't attach so big file on mailing
> >>> lists. Next time plase share them via e.g. pastebin. The output was a
> >>> capture from your terminal, which made the output more difficult to
> >>> read. Hint: You can/could use perf --stdio and place it in a file
> >>> instead.
> >>>
> >>> The output (extracted below) didn't show who called 'do_raw_spin_lock',
> >>> BUT it showed another interesting thing. The kernel code
> >>> __dev_queue_xmit() in might create route dst-cache problem for itself(?),
> >>> as it will first call skb_dst_force() and then skb_dst_drop() when the
> >>> packet is transmitted on a VLAN.
> >>>
> >>> static int __dev_queue_xmit(struct sk_buff *skb, void *accel_priv)
> >>> {
> >>> [...]
> >>> /* If device/qdisc don't need skb->dst, release it right now while
> >>> * its hot in this cpu cache.
> >>> */
> >>> if (dev->priv_flags & IFF_XMIT_DST_RELEASE)
> >>> skb_dst_drop(skb);
> >>> else
> >>> skb_dst_force(skb);
> >>>
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
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