Date: Fri, 5 Feb 2016 18:05:32 +0000 From: "Meyer, Wolfgang" <wolfgang.meyer@hob.de> To: "'K. Macy'" <kmacy@freebsd.org>, Allan Jude <allanjude@freebsd.org> Cc: "freebsd-performance@freebsd.org" <freebsd-performance@freebsd.org> Subject: RE: ixgbe: Network performance tuning (#TCP connections) Message-ID: <EC88118611AE564AB0B10C6A4569004D0137D58050@HOBEX11.hob.de> In-Reply-To: <CAHM0Q_NeXBeQvctMA8oaaUtWVncKzFX7qxbasWCoR04fGUP-dw@mail.gmail.com> References: <EC88118611AE564AB0B10C6A4569004D0137D57AEB@HOBEX11.hob.de> <56B23DEA.1060307@freebsd.org> <CAHM0Q_NeXBeQvctMA8oaaUtWVncKzFX7qxbasWCoR04fGUP-dw@mail.gmail.com>
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> -----Original Message----- > From: owner-freebsd-performance@freebsd.org [mailto:owner-freebsd- > performance@freebsd.org] On Behalf Of K. Macy > Sent: Mittwoch, 3. Februar 2016 20:31 > To: Allan Jude > Cc: freebsd-performance@freebsd.org > Subject: Re: ixgbe: Network performance tuning (#TCP connections) > > Also - check for txq overruns and rxq drops in sysctl. 64 is very low on > FreeBSD. You may also look in to increasing the size of your pcb hash tab= le. > > > > On Wed, Feb 3, 2016 at 9:50 AM, Allan Jude <allanjude@freebsd.org> wrote: > > On 2016-02-03 08:37, Meyer, Wolfgang wrote: > >> Hello, > >> > >> we are evaluating network performance on a DELL-Server (PowerEdge > R930 with 4 Sockets, hw.model: Intel(R) Xeon(R) CPU E7-8891 v3 @ 2.80GHz) > with 10 GbE-Cards. We use programs that on server side accepts connection= s > on a IP-address+port from the client side and after establishing the > connection data is sent in turns between server and client in a predefine= d > pattern (server side sends more data than client side) with sleeps in > between the send phases. The test set-up is chosen in such way that every > client process initiates 500 connections handled in threads and on the se= rver > side each process representing an IP/Port pair also handles 500 connectio= ns > in threads. > >> > >> The number of connections is then increased and the overall network > througput is observed using nload. On FreeBSD (on server side) roughly at > 50,000 connections errors begin to occur and the overall throughput won't > increase further with more connections. With Linux on the server side it = is > possible to establish more than 120,000 connections and at 50,000 > connections the overall throughput ist double that of FreeBSD with the sa= me > sending pattern. Furthermore system load on FreeBSD is much higher with > 50 % system usage on each core and 80 % interrupt usage on the 8 cores > handling the interrupt queues for the NIC. In comparison Linux has <10 % > system usage, <10 % user usage and about 15 % interrupt usage on the 16 > cores handling the network interrupts for 50,000 connections. > >> > >> Varying the numbers for the NIC interrupt queues won't change the > performance (rather worsens the situation). Disabling Hyperthreading > (utilising 40 cores) degrades the performance. Increasing MAXCPU to utili= se > all 80 cores won't improve compared to 64 cores, atkbd and uart had to be > disabled to avoid kernel panics with increased MAXCPU (thanks to Andre > Oppermann for investigating this). Initiallly the tests were made on 10.2 > Release, later I switched to 10 Stable (later with ixgbe driver version 3= .1.0) > but that didn't change the numbers. > >> > >> Some sysctl configurables were modified along the network performance > guidelines found on the net (e.g. > https://calomel.org/freebsd_network_tuning.html, > https://www.freebsd.org/doc/handbook/configtuning-kernel-limits.html, > https://pleiades.ucsc.edu/hyades/FreeBSD_Network_Tuning) but most of > them didn't have any measuarable impact. Final sysctl.conf and loader.con= f > settings see below. Actually the only tunables that provided any > improvement were identified to be hw.ix.txd, and hw.ix.rxd that were > reduced (!) to the minimum value of 64 and hw.ix.tx_process_limit and > hw.ix.rx_process_limit that were set to -1. > >> > >> Any ideas what tunables might be changed to get a higher number of TCP > connections (it's not a question of the overall throughput as changing th= e > sending pattern allows me to fully utilise the 10Gb bandwidth)? How can I > determine where the kernel is spending its time that causes the high CPU > load? Any pointers are highly appreciated, I can't believe that there is = such a > blatant difference in network performance compared to Linux. > >> > >> Regards, > >> Wolfgang > >> > > > > I wonder if this might be NUMA related. Specifically, it might help to > > make sure that the 8 CPU cores that the NIC queues are pinned to, are > > on the same CPU that is backing the PCI-E slot that the NIC is in. > > > > > > -- > > Allan Jude > > As I was telling in my original message, the rxd and txd values were more o= r less the only ones that changed my numbers to the better when reducing th= em. Not that I understood that behaviour but a double-check now revealed th= at I stand corrected on this observation. Raising the value (to 1024) now d= id not only degrade througput to my original bad numbers but to the opposit= e slightly improved it (but only barely measurable compared to measurement = variation). Don't know what cross interaction was leading to my original ob= servation. Concerning pcb hash table size I only found net.inet.sctp.pcbhashsize and t= hat had no influence. Not sure whether sctp plays a role at all in my probl= em. Regards, Wolfgang Meyer ________________________________ Follow HOB: - HOB: http://www.hob.de/redirect/hob.html - Xing: http://www.hob.de/redirect/xing.html - LinkedIn: http://www.hob.de/redirect/linkedin.html - HOBLink Mobile: http://www.hob.de/redirect/hoblinkmobile.html - Facebook: http://www.hob.de/redirect/facebook.html - Twitter: http://www.hob.de/redirect/twitter.html - YouTube: http://www.hob.de/redirect/youtube.html - E-Mail: http://www.hob.de/redirect/mail.html HOB GmbH & Co. KG Schwadermuehlstr. 3 D-90556 Cadolzburg Geschaeftsfuehrung: Klaus Brandstaetter, Zoran Adamovic AG Fuerth, HRA 5180 Steuer-Nr. 218/163/00107 USt-ID-Nr. DE 132747002 Komplementaerin HOB electronic Beteiligungs GmbH AG Fuerth, HRB 3416
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