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--- documentation:technical_docs:performance [2019/11/21 17:27] – [Disabling Hyper Threading] olivier
+++ documentation:technical_docs:performance [2020/01/18 01:03] – [Polling mode (very old hardware)] olivier
@@ Line 27: / Line 27: @@
   * [[http://www.telematica.polito.it/oldsite/courmayeur06/papers/06-A.2.1.pdf|RFC2544 Performance Evaluation for a Linux Based Open Router]] (2006, June)
   * [[http://data.guug.de/slides/lk2008/10G_preso_lk2008.pdf|Towards 10Gb/s open-source routing]] (2008): Include an hardware comparison between a "real" router and a PC.
+  * [[https://wiki.fd.io/images/7/7b/Performance_Consideration_for_packet_processing_on_Intel_Architecture.pptx|Performance consideration for packet processing on Intel Architecture (ppt)]]
 ==== FreeBSD ====
@@ Line 107: / Line 108: @@
 BSDRP is currently following FreeBSD 12-stable branch, to try to have a mix between recent features and stability.
-==== Disabling Hyper Threading (HT) ====
+==== Disabling Hyper Threading (on specific CPU only) ====
-By default, lot's of multi-queue NIC drivers create one queue per core.
+By default a multi-queue NIC drivers create one queue per core.
-But "logical" cores didn't help at all for managing interrupts generated by high speed NIC (this is not true on 13-head since [[https://svnweb.freebsd.org/base?view=revision&revision=354338|r354338]] and the new machdep.hyperthreading_intr_allowed that allow interrupts on HTT logical CPUs.
+But on some older CPU (like Xeon E5-2650 V1) those logical cores didn't help at all for managing interrupts generated by high speed NIC.
 HT can be disabled with this command:
@@ Line 117: / Line 118: @@
 </code>
-Here is an example on a 8cores x hardware threads Intel CPU and 10G Chelsio NIC:
+Here is an example on a Xeon E5 2650 (8c,16t) and 10G Chelsio NIC where it improve performance by disabling HT:
 <code>
-x HT-enabled-8rxq(default).packets-per-seconds
+x HT-enabled-8rxq(default): inet packets-per-second forwarded
-+ HT-enabled-16rxq.packets-per-seconds
++ HT-enabled-16rxq: inet packets-per-second forwarded
-* HT-disabled.packets-per-seconds
+* HT-disabled-8rxq: inet packets-per-seconds forwarded
 +--------------------------------------------------------------------------+
 |                                                                        **|
@@ Line 144: / Line 145: @@
 </code>
-There is a benefit of about 24% to disable hyper threading.
+There is a benefit of about 24% to disable hyper threading on this old CPU.
+But here is another example where there is a benefit to kept it enabled (and with the NIC configured to uses all the treads) on Xeon E5 2650L (10c, 20t):
+<code>
+x HT on, 8q (default): inet4 packets-per-second forwarded
++ HT off, 8q: inet4 packets-per-second forwarded
+* HT on, 16q: inet4 packets-per-second forwarded
++--------------------------------------------------------------------------+
+|x x              ++                                                   *  *|
+|x xx            +++                                                 * *  *|
+||AM|            |A_|                                                |_MA_||
++--------------------------------------------------------------------------+
+    N           Min           Max        Median           Avg        Stddev
+x   5       4265579     4433699.5     4409249.5     4359580.3       81559.4
++   5       5257621       5443012       5372493     5372693.5     73316.243
+Difference at 95.0% confidence
+.01311e+06 +/- 113098
+.2388% +/- 2.94299%
+        (Student's t, pooled s = 77547.4)
+*   5       8566972       8917315     8734750.5     8769616.1     147186.74
+Difference at 95.0% confidence
+.41004e+06 +/- 173536
+.157% +/- 5.21388%
+        (Student's t, pooled s = 118987)
+</code>
 ==== fastforwarding ====
@@ Line 229: / Line 255: @@
 {{documentation:technical_docs:entropy_source_impact.png|Impact of disabling some entropy source on FreeBSD forwarding performance}}
-==== Polling mode ====
-Polling can be used in 2 cases:
-   * On **old hardware only** (where Ethernet card doesn't support **Intelligent interrupt management**), using the polling mode can improve performance by reducing CPU interrupt
-   * When used [[http://lists.freebsd.org/pipermail/freebsd-net/2013-May/035626.html|for usage in a Virtual Machine]] but don't forgot to [[https://lists.freebsd.org/pipermail/freebsd-net/2015-March/041657.html|overwrite the default HZ value in this case too]].
-For enabling polling mode:
-  - Edit /etc/rc.conf.misc and replace //polling_enable="NO"// by //polling_enable="YES"//
-  - Execute: service polling start
-=== NIC drivers compatibility matrix ===
-BSDRP can use some special features on somes NIC:
-  * [[http://www.freebsd.org/cgi/man.cgi?query=polling|Ethernet device polling]] for high performance with Ethernet controllers that didn't include interrupt management feature or [[http://info.iet.unipi.it/~luigi/papers/20130520-rizzo-vm.pdf|for usage in a VM]].
-  * [[http://www.freebsd.org/cgi/man.cgi?query=altq|ALTQ]] for queuing, but try to use [[http://www.freebsd.org/cgi/man.cgi?query=dummynet|dummynet]] in place
-And only theses devices support these modes:
-^ name      ^ Description    ^ Polling   ^ ALTQ       ^
-| ae  | Attansic/Atheros L2 FastEthernet controller driver | no | yes |
-| age | Attansic/Atheros L1 Gigabit Ethernet driver | no | yes |
-| alc | Atheros AR813x/AR815x Gigabit/Fast Ethernet driver | no | yes |
-| ale | Atheros AR8121/AR8113/AR8114 Gigabit/Fast Ethernet driver | no | yes |
-| bce | Broadcom NetXtreme II (BCM5706/5708/5709/5716) PCI/PCIe Gigabit Ethernet adapter driver | no | yes |
-| bfe | Broadcom BCM4401 Ethernet Device Driver | no | yes |
-| bge | Broadcom BCM570x/5714/5721/5722/5750/5751/5752/5789 PCI Gigabit Ethernet adapter driver | yes | yes |
-| cas | Sun Cassini/Cassini+ and National Semiconductor DP83065 Saturn Gigabit Ethernet driver  | no | yes |
-| cxgbe | Chelsio T4 and T5 based 40Gb, 10Gb, and 1Gb Ethernet adapter driver | no | yes |
-| dc | DEC/Intel 21143 and clone 10/100 Ethernet driver | yes | yes |
-| de | DEC DC21x4x Ethernet device driver | no | yes |
-| ed | NE-2000 and WD-80x3 Ethernet driver | no | yes |
-| em | Intel(R) PRO/1000 Gigabit Ethernet adapter driver | yes | yes |
-| et | Agere ET1310 10/100/Gigabit Ethernet driver | no | yes |
-| ep | Ethernet driver for 3Com Etherlink III (3c5x9) interfaces | no | yes |
-| fxp | Intel EtherExpress PRO/100 Ethernet device driver | yes | yes |
-| gem | ERI/GEM/GMAC Ethernet device driver | no | yes |
-| hme | Sun Microelectronics STP2002-STQ Ethernet interfaces device driver | no | yes |
-| igb | Intel(R) PRO/1000 PCI Express Gigabit Ethernet adapter driver | yes | needs IGB_LEGACY_TX |
-| ixgb(e) | Intel(R) 10Gb Ethernet driver | yes | needs IGB_LEGACY_TX |
-| jme | JMicron Gigabit/Fast Ethernet driver | no | yes |
-| le | AMD Am7900 LANCE and Am79C9xx ILACC/PCnet Ethernet interface driver | no | yes |
-| msk | Marvell/SysKonnect Yukon II Gigabit Ethernet adapter driver | no | yes |
-| mxge | Myricom Myri10GE 10 Gigabit Ethernet adapter driver | no | yes |
-| my | Myson Technology Ethernet PCI driver | no | yes |
-| nfe | NVIDIA nForce MCP Ethernet driver | yes | yes |
-| nge | National Semiconductor PCI Gigabit Ethernet adapter driver | yes | no |
-| nve | NVIDIA nForce MCP Networking Adapter device driver | no | yes |
-| qlxgb | QLogic 10 Gigabit Ethernet & CNA Adapter Driver | no | yes |
-| re | RealTek 8139C+/8169/816xS/811xS/8101E PCI/PCIe Ethernet adapter driver | yes | yes |
-| rl | RealTek 8129/8139 Fast Ethernet device driver | yes | yes |
-| sf | Adaptec AIC‐6915 "Starfire" PCI Fast Ethernet adapter driver | yes | yes |
-| sge | Silicon Integrated Systems SiS190/191 Fast/Gigabit Ethernet driver | no | yes |
-| sis | SiS 900, SiS 7016 and NS DP83815/DP83816 Fast Ethernet device driver | yes | yes |
-| sk | SysKonnect SK-984x and SK-982x PCI Gigabit Ethernet adapter driver | yes | yes |
-| ste | Sundance Technologies ST201 Fast Ethernet device driver | no | yes |
-| stge | Sundance/Tamarack TC9021 Gigabit Ethernet adapter driver | yes | yes |
-| ti | Alteon Networks Tigon I and Tigon II Gigabit Ethernet driver | no | yes |
-| txp | 3Com 3XP Typhoon/Sidewinder (3CR990) Ethernet interface | no | yes |
-| vge | VIA Networking Technologies VT6122 PCI Gigabit Ethernet adapter driver | yes | yes |
-| vr | VIA Technologies Rhine I/II/III Ethernet device driver | yes | yes |
-| xl | 3Com Etherlink XL and Fast Etherlink XL Ethernet device driver | yes | yes |
-Using others NIC will works too :-)
 ==== NIC drivers tuning ====