From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm1-x334.google.com (mail-wm1-x334.google.com [IPv6:2a00:1450:4864:20::334]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id A920C3B29D for ; Wed, 19 Oct 2022 12:13:17 -0400 (EDT) Received: by mail-wm1-x334.google.com with SMTP id m29-20020a05600c3b1d00b003c6bf423c71so389540wms.0 for ; Wed, 19 Oct 2022 09:13:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=Dlj4o/csof07HDpddXkCiSv6jYM584hFAVgX9kKHyaU=; b=IrIYQ0EtrLVmi3jPcGeXosd05uBTyXILGQZIsMElr00VVoTltLeWV66ncYbfe34GPI h5E7wyvU/kaRDkbAfFppevuWhJkrFGvd+GeFsj/NR2/31l96FIgmfH1nUkAxEh7FjC8G IfyzbEWJis5lf+IMn5ldUqNptcqYa2bE5hvbSnPvDDBj4R7jxj7Mi0oi9aI6hn8+mRqv rmuhehgUOBsDneIGHBcR6RzrFgCiG/+ipq+CbKuv2klORtA/DpQ6VB3+Be8uUFMKHJDt +R16EMyBl5LiOnMwfrxiX52kfIG5BGjJG6NhsIH8V7geX5dsy6zyi4RdoorWxE1kodxl wcGw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Dlj4o/csof07HDpddXkCiSv6jYM584hFAVgX9kKHyaU=; b=1nsxexvmox338UrtoswbgrSZ9aMuPQG4UqNMxVEuA1EdI7b/nuFjFM374X8CagmiLv OkDVFH/hMUtcBO9ymWjvdJbO1Lw2C3aLXexUu+Iq9Eo5IhyBvjbdkyP4S13WmzzcYDU5 DIcuD2mHDQn+SBdRzjYp5vteO2aEFn//DeH2tbi/r+0cHfs+cfVbEhCEkDC2qTDmYAE+ piW3IaJCJZPJjm7GyzxbSqpl9qk3hKyQFQnPRF6/1+TukhDHg0CCBbRivxPNb1mlPsiy R1uxOoi3Nxdt8129H6Y6ZKnICKkF3sTpOATbo+R0sYbfDxMYgxQDfkocVKQFKci9JBnk d8Bw== X-Gm-Message-State: ACrzQf2bTz/UN4bghu+j7leDxzzHEvwYcSfjg/Xfzjn7Naa1i6TEeLeM 6qUrz3MlnroFFfIMb5/scQfV6wCY21P5fxUCGfQ= X-Google-Smtp-Source: AMsMyM4zdxAmFp40Z/m1LjvINu0uaJX4e1KwQTjB73OLFeFmdfipiMfTv7Rp/ZXH0wRqu0QL7zB9ejdnr3sneJIXBfQ= X-Received: by 2002:a05:600c:1906:b0:3c6:f83e:d15f with SMTP id j6-20020a05600c190600b003c6f83ed15fmr11007809wmq.205.1666195995921; Wed, 19 Oct 2022 09:13:15 -0700 (PDT) MIME-Version: 1.0 References: <87bkqatu61.fsf@toke.dk> <759c25c6fd54dceccc00eada5ccf5358d2d1c20c.camel@kau.se> In-Reply-To: From: Dave Taht Date: Wed, 19 Oct 2022 09:13:02 -0700 Message-ID: To: Herbert Wolverson Cc: "libreqos@lists.bufferbloat.net" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [LibreQoS] In BPF pping - so far X-BeenThere: libreqos@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Many ISPs need the kinds of quality shaping cake can do List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Oct 2022 16:13:17 -0000 flent outputs a flent.gz file that I can parse and plot 20 differnt ways. Also the graphing tools work on osx On Wed, Oct 19, 2022 at 9:11 AM Herbert Wolverson via LibreQoS wrote: > > That's true. The 12th gen does seem to have some "special" features... ma= kes for a nice writing platform > (this box is primarily my "write books and articles" machine). I'll be do= ing a wider test on a more normal > platform, probably at the weekend (with real traffic, hence the delay - h= ave to find a time in which I > minimize disruption) > > On Wed, Oct 19, 2022 at 10:49 AM dan wrote: >> >> Those 'efficiency' threads in Intel 12th gen should probably be addresse= d as well. You can't turn them off in BIOS. >> >> On Wed, Oct 19, 2022 at 8:48 AM Robert Chac=C3=B3n via LibreQoS wrote: >>> >>> Awesome work on this! >>> I suspect there should be a slight performance bump once Hyperthreading= is disabled and efficient power management is off. >>> Hyperthreading/SMT always messes with HTB performance when I leave it o= n. Thank you for mentioning that - I now went ahead and added instructions = on disabling hyperthreading on the Wiki for new users. >>> Super promising results! >>> Interested to see what throughput is with xdp-cpumap-tc vs cpumap-pping= . So far in your VM setup it seems to be doing very well. >>> >>> On Wed, Oct 19, 2022 at 8:06 AM Herbert Wolverson via LibreQoS wrote: >>>> >>>> Also, I forgot to mention that I *think* the current version has remov= ed the requirement that the inbound >>>> and outbound classifiers be placed on the same CPU. I know interduo wa= s particularly keen on packing >>>> upload into fewer cores. I'll add that to my list of things to test. >>>> >>>> On Wed, Oct 19, 2022 at 9:01 AM Herbert Wolverson wrote: >>>>> >>>>> I'll definitely take a look - that does look interesting. I don't hav= e X11 on any of my test VMs, but >>>>> it looks like it can work without the GUI. >>>>> >>>>> Thanks! >>>>> >>>>> On Wed, Oct 19, 2022 at 8:58 AM Dave Taht wrote= : >>>>>> >>>>>> could I coax you to adopt flent? >>>>>> >>>>>> apt-get install flent netperf irtt fping >>>>>> >>>>>> You sometimes have to compile netperf yourself with --enable-demo on >>>>>> some systems. >>>>>> There are a bunch of python libs neede for the gui, but only on the = client. >>>>>> >>>>>> Then you can run a really gnarly test series and plot the results ov= er time. >>>>>> >>>>>> flent --socket-stats --step-size=3D.05 -t 'the-test-conditions' -H >>>>>> the_server_name rrul # 110 other tests >>>>>> >>>>>> >>>>>> On Wed, Oct 19, 2022 at 6:44 AM Herbert Wolverson via LibreQoS >>>>>> wrote: >>>>>> > >>>>>> > Hey, >>>>>> > >>>>>> > Testing the current version ( https://github.com/thebracket/cpumap= -pping-hackjob ), it's doing better than I hoped. This build has shared (no= t per-cpu) maps, and a userspace daemon (xdp_pping) to extract and reset st= ats. >>>>>> > >>>>>> > My testing environment has grown a bit: >>>>>> > * ShaperVM - running Ubuntu Server and LibreQoS, with the new cpum= ap-pping-hackjob version of xdp-cpumap. >>>>>> > * ExtTest - running Ubuntu Server, set as 10.64.1.1. Hosts an iper= f server. >>>>>> > * ClientInt1 - running Ubuntu Server (minimal), set as 10.64.1.2. = Hosts iperf client. >>>>>> > * ClientInt2 - running Ubuntu Server (minimal), set as 10.64.1.3. = Hosts iperf client. >>>>>> > >>>>>> > ClientInt1, ClientInt2 and one interface (LAN facing) of ShaperVM = are on a virtual switch. >>>>>> > ExtTest and the other interface (WAN facing) of ShaperVM are on a = different virtual switch. >>>>>> > >>>>>> > These are all on a host machine running Windows 11, a core i7 12th= gen, 32 Gb RAM and fast SSD setup. >>>>>> > >>>>>> > TEST 1: DUAL STREAMS, LOW THROUGHPUT >>>>>> > >>>>>> > For this test, LibreQoS is configured: >>>>>> > * Two APs, each with 5gbit/s max. >>>>>> > * 100.64.1.2 and 100.64.1.3 setup as CPEs, each limited to about 1= 00mbit/s. They map to 1:5 and 2:5 respectively (separate CPUs). >>>>>> > * Set to use Cake >>>>>> > >>>>>> > On each client, roughly simultaneously run: iperf -c 100.64.1.1 -t= 500 (for a long run). Running xdp_pping yields correct results: >>>>>> > >>>>>> > [ >>>>>> > {"tc":"1:5", "avg" : 4, "min" : 3, "max" : 5, "samples" : 11}, >>>>>> > {"tc":"2:5", "avg" : 4, "min" : 3, "max" : 5, "samples" : 11}, >>>>>> > {}] >>>>>> > >>>>>> > Or when I waited a while to gather/reset: >>>>>> > >>>>>> > [ >>>>>> > {"tc":"1:5", "avg" : 4, "min" : 3, "max" : 6, "samples" : 60}, >>>>>> > {"tc":"2:5", "avg" : 4, "min" : 3, "max" : 5, "samples" : 60}, >>>>>> > {}] >>>>>> > >>>>>> > The ShaperVM shows no errors, just periodic logging that it is rec= ording data. CPU is about 2-3% on two CPUs, zero on the others (as expecte= d). >>>>>> > >>>>>> > After 500 seconds of continual iperfing, each client reported a th= roughput of 104 Mbit/sec and 6.06 GBytes of data transmitted. >>>>>> > >>>>>> > So for smaller streams, I'd call this a success. >>>>>> > >>>>>> > TEST 2: DUAL STREAMS, HIGH THROUGHPUT >>>>>> > >>>>>> > For this test, LibreQoS is configured: >>>>>> > * Two APs, each with 5gb/s max. >>>>>> > * 100.64.1.2 and 100.64.1.3 setup as CPEs, each limited to 5Gbit/s= ! Mapped to 1:5 and 2:5 respectively (separate CPUs). >>>>>> > >>>>>> > Run iperfc -c 100.64.1.1 -t 500 on each client at the same time. >>>>>> > >>>>>> > xdp_pping shows results, too: >>>>>> > >>>>>> > [ >>>>>> > {"tc":"1:5", "avg" : 4, "min" : 1, "max" : 7, "samples" : 58}, >>>>>> > {"tc":"2:5", "avg" : 7, "min" : 3, "max" : 11, "samples" : 58}, >>>>>> > {}] >>>>>> > >>>>>> > [ >>>>>> > {"tc":"1:5", "avg" : 5, "min" : 4, "max" : 8, "samples" : 13}, >>>>>> > {"tc":"2:5", "avg" : 8, "min" : 7, "max" : 10, "samples" : 13}, >>>>>> > {}] >>>>>> > >>>>>> > The ShaperVM shows two CPUs pegging between 70 and 90 percent. >>>>>> > >>>>>> > After 500 seconds of continual iperfing, each client reported a th= roughput of 2.72 Gbits/sec (158 GBytes) and 3.89 Gbits/sec and 226 GBytes. >>>>>> > >>>>>> > Maxing out HyperV like this is inducing a bit of latency (which is= to be expected), but it's not bad. I also forgot to disable hyperthreading= , and looking at the host performance it is sometimes running the second vi= rtual CPU on an underpowered "fake" CPU. >>>>>> > >>>>>> > So for two large streams, I think we're doing pretty well also! >>>>>> > >>>>>> > TEST 3: DUAL STREAMS, SINGLE CPU >>>>>> > >>>>>> > This test is designed to try and blow things up. It's the same as = test 2, but both CPEs are set to the same CPU (1), using TC handles 1:5 and= 1:6. >>>>>> > >>>>>> > ShaperVM CPU1 maxed out in the high 90s, the other CPUs were idle.= The pping stats start to show a bit of degradation in performance for poun= ding it so hard: >>>>>> > >>>>>> > [ >>>>>> > {"tc":"1:6", "avg" : 10, "min" : 9, "max" : 19, "samples" : 24}, >>>>>> > {"tc":"1:5", "avg" : 10, "min" : 8, "max" : 18, "samples" : 24}, >>>>>> > {}] >>>>>> > >>>>>> > For whatever reason, it smoothed out over time: >>>>>> > >>>>>> > [ >>>>>> > {"tc":"1:6", "avg" : 10, "min" : 9, "max" : 12, "samples" : 50}, >>>>>> > {"tc":"1:5", "avg" : 10, "min" : 8, "max" : 13, "samples" : 50}, >>>>>> > {}] >>>>>> > >>>>>> > Surprisingly (to me), I didn't encounter errors. Each client recei= ved 2.22 Gbit/s performance, over 129 Gbytes of data. >>>>>> > >>>>>> > TEST 4: DUAL STREAMS, 50 SUB-STREAMS >>>>>> > >>>>>> > This test is also designed to break things. Same as test 3, but us= ing iperf -c 100.64.1.1 -P 50 -t 120 - 50 substreams, to try and really tax= the flow tracking. (Shorter time window because I really wanted to go and = find coffee) >>>>>> > >>>>>> > ShaperVM CPU sat at around 80-97%, tending towards 97%. pping resu= lts show that this torture test is worsening performance, and there's alway= s lots of samples in the buffer: >>>>>> > >>>>>> > [ >>>>>> > {"tc":"1:6", "avg" : 23, "min" : 19, "max" : 27, "samples" : 49}, >>>>>> > {"tc":"1:5", "avg" : 24, "min" : 19, "max" : 27, "samples" : 49}, >>>>>> > {}] >>>>>> > >>>>>> > This test also ran better than I expected. You can definitely see = some latency creeping in as I make the system work hard. Each VM showed aro= und 2.4 Gbit/s in total performance at the end of the iperf session. There'= s definitely some latency creeping in, which is expected - but I'm not sure= I expected quite that much. >>>>>> > >>>>>> > WHAT'S NEXT & CONCLUSION >>>>>> > >>>>>> > I noticed that I forgot to turn off efficient power management on = my VMs and host, and left Hyperthreading on by mistake. So that hurts overa= ll performance. >>>>>> > >>>>>> > The base system seems to be working pretty solidly, at least for s= mall tests.Next up, I'll be removing extraneous debug reporting code, remov= ing some code paths that don't do anything but report, and looking for any = small optimization opportunities. I'll then re-run these tests. Once that's= done, I hope to find a maintenance window on my WISP and try it with actua= l traffic. >>>>>> > >>>>>> > I also need to re-run these tests without the pping system to prov= ide some before/after analysis. >>>>>> > >>>>>> > On Tue, Oct 18, 2022 at 1:01 PM Herbert Wolverson wrote: >>>>>> >> >>>>>> >> It's probably not entirely thread-safe right now (ran into some i= ssues reading per_cpu maps back from userspace; hopefully, I'll get that fi= gured out) - but the commits I just pushed have it basically working on sin= gle-stream testing. :-) >>>>>> >> >>>>>> >> Setup cpumap as usual, and periodically run xdp-pping. This gives= you per-connection RTT information in JSON: >>>>>> >> >>>>>> >> [ >>>>>> >> {"tc":"1:5", "avg" : 5, "min" : 5, "max" : 5, "samples" : 1}, >>>>>> >> {}] >>>>>> >> >>>>>> >> (With the extra {} because I'm not tracking the tail and haven't = done comma removal). The tool also empties the various maps used to gather = data, acting as a "reset" point. There's a max of 60 samples per queue, in = a ringbuffer setup (so newest will start to overwrite the oldest). >>>>>> >> >>>>>> >> I'll start trying to test on a larger scale now. >>>>>> >> >>>>>> >> On Mon, Oct 17, 2022 at 3:34 PM Robert Chac=C3=B3n wrote: >>>>>> >>> >>>>>> >>> Hey Herbert, >>>>>> >>> >>>>>> >>> Fantastic work! Super exciting to see this coming together, espe= cially so quickly. >>>>>> >>> I'll test it soon. >>>>>> >>> I understand and agree with your decision to omit certain featur= es (ICMP tracking,DNS tracking, etc) to optimize performance for our use ca= se. Like you said, in order to merge the functionality without a performanc= e hit, merging them is sort of the only way right now. Otherwise there woul= d be a lot of redundancy and lost throughput for an ISP's use. Though hopef= ully long term there will be a way to keep all projects working independent= ly but interoperably with a plugin system of some kind. >>>>>> >>> >>>>>> >>> By the way, I'm making some headway on LibreQoS v1.3. Focusing o= n optimizations for high sub counts (8000+ subs) as well as stateful change= s to the queue structure. >>>>>> >>> I'm working to set up a physical lab to test high throughput and= high client count scenarios. >>>>>> >>> When testing beyond ~32,000 filters we get "no space left on dev= ice" from xdp-cpumap-tc, which I think relates to the bpf map size limitati= on you mentioned. Maybe in the coming months we can take a look at that. >>>>>> >>> >>>>>> >>> Anyway great work on the cpumap-pping program! Excited to see mo= re on this. >>>>>> >>> >>>>>> >>> Thanks, >>>>>> >>> Robert >>>>>> >>> >>>>>> >>> On Mon, Oct 17, 2022 at 12:45 PM Herbert Wolverson via LibreQoS = wrote: >>>>>> >>>> >>>>>> >>>> Hey, >>>>>> >>>> >>>>>> >>>> My current (unfinished) progress on this is now available here:= https://github.com/thebracket/cpumap-pping-hackjob >>>>>> >>>> >>>>>> >>>> I mean it about the warnings, this isn't at all stable, debugge= d - and can't promise that it won't unleash the nasal demons >>>>>> >>>> (to use a popular C++ phrase). The name is descriptive! ;-) >>>>>> >>>> >>>>>> >>>> With that said, I'm pretty happy so far: >>>>>> >>>> >>>>>> >>>> * It runs only on the classifier - which xdp-cpumap-tc has nice= ly shunted onto a dedicated CPU. It has to run on both >>>>>> >>>> the inbound and outbound classifiers, since otherwise it woul= d only see half the conversation. >>>>>> >>>> * It does assume that your ingress and egress CPUs are mapped t= o the same interface; I do that anyway in BracketQoS. Not doing >>>>>> >>>> that opens up a potential world of pain, since writes to the = shared maps would require a locking scheme. Too much locking, and you lose = all of the benefit of using multiple CPUs to begin with. >>>>>> >>>> * It is pretty wasteful of RAM, but most of the shaper systems = I've worked with have lots of it. >>>>>> >>>> * I've been gradually removing features that I don't want for B= racketQoS. A hypothetical future "useful to everyone" version wouldn't do t= hat. >>>>>> >>>> * Rate limiting is working, but I removed the requirement for a= shared configuration provided from userland - so right now it's always set= to report at 1 second intervals per stream. >>>>>> >>>> >>>>>> >>>> My testbed is currently 3 Hyper-V VMs - a simple "client" and "= world", and a "shaper" VM in between running a slightly hacked-up LibreQoS. >>>>>> >>>> iperf from "client" to "world" (with Libre set to allow 10gbit/= s max, via a cake/HTB queue setup) is around 5 gbit/s at present, on my >>>>>> >>>> test PC (the host is a core i7, 12th gen, 12 cores - 64gb RAM a= nd fast SSDs) >>>>>> >>>> >>>>>> >>>> Output currently consists of debug messages reading: >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 515.399222: bpf_trace_pr= intk: (tc) Flow open event >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 515.399239: bpf_trace_pr= intk: (tc) Send performance event (5,1), 374696 >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 515.399466: bpf_trace_pr= intk: (tc) Flow open event >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 515.399475: bpf_trace_pr= intk: (tc) Send performance event (5,1), 247069 >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 516.405151: bpf_trace_pr= intk: (tc) Send performance event (5,1), 5217155 >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 517.405248: bpf_trace_pr= intk: (tc) Send performance event (5,1), 4515394 >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 518.406117: bpf_trace_pr= intk: (tc) Send performance event (5,1), 4481289 >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 519.406255: bpf_trace_pr= intk: (tc) Send performance event (5,1), 4255268 >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 520.407864: bpf_trace_pr= intk: (tc) Send performance event (5,1), 5249493 >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 521.406664: bpf_trace_pr= intk: (tc) Send performance event (5,1), 3795993 >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 522.407469: bpf_trace_pr= intk: (tc) Send performance event (5,1), 3949519 >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 523.408126: bpf_trace_pr= intk: (tc) Send performance event (5,1), 4365335 >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 524.408929: bpf_trace_pr= intk: (tc) Send performance event (5,1), 4154910 >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 525.410048: bpf_trace_pr= intk: (tc) Send performance event (5,1), 4405582 >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 525.434080: bpf_trace_pr= intk: (tc) Send flow event >>>>>> >>>> cpumap/0/map:4-1371 [000] D..2. 525.482714: bpf_trace_pr= intk: (tc) Send flow event >>>>>> >>>> >>>>>> >>>> The times haven't been tweaked yet. The (5,1) is tc handle majo= r/minor, allocated by the xdp-cpumap parent. >>>>>> >>>> I get pretty low latency between VMs; I'll set up a test with s= ome real-world data very soon. >>>>>> >>>> >>>>>> >>>> I plan to keep hacking away, but feel free to take a peek. >>>>>> >>>> >>>>>> >>>> Thanks, >>>>>> >>>> Herbert >>>>>> >>>> >>>>>> >>>> On Mon, Oct 17, 2022 at 10:14 AM Simon Sundberg wrote: >>>>>> >>>>> >>>>>> >>>>> Hi, thanks for adding me to the conversation. Just a couple of= quick >>>>>> >>>>> notes. >>>>>> >>>>> >>>>>> >>>>> On Mon, 2022-10-17 at 16:13 +0200, Toke H=C3=B8iland-J=C3=B8rg= ensen wrote: >>>>>> >>>>> > [ Adding Simon to Cc ] >>>>>> >>>>> > >>>>>> >>>>> > Herbert Wolverson via LibreQoS writes: >>>>>> >>>>> > >>>>>> >>>>> > > Hey, >>>>>> >>>>> > > >>>>>> >>>>> > > I've had some pretty good success with merging xdp-pping ( >>>>>> >>>>> > > https://github.com/xdp-project/bpf-examples/blob/master/pp= ing/pping.h ) >>>>>> >>>>> > > into xdp-cpumap-tc ( https://github.com/xdp-project/xdp-cp= umap-tc ). >>>>>> >>>>> > > >>>>>> >>>>> > > I ported over most of the xdp-pping code, and then changed= the entry point >>>>>> >>>>> > > and packet parsing code to make use of the work already do= ne in >>>>>> >>>>> > > xdp-cpumap-tc (it's already parsed a big chunk of the pack= et, no need to do >>>>>> >>>>> > > it twice). Then I switched the maps to per-cpu maps, and h= ad to pin them - >>>>>> >>>>> > > otherwise the two tc instances don't properly share data. >>>>>> >>>>> > > >>>>>> >>>>> >>>>>> >>>>> I guess the xdp-cpumap-tc ensures that the same flow is proces= sed on >>>>>> >>>>> the same CPU core at both ingress or egress. Otherwise, if a f= low may >>>>>> >>>>> be processed by different cores on ingress and egress the per-= CPU maps >>>>>> >>>>> will not really work reliably as each core will have a differe= nt view >>>>>> >>>>> on the state of the flow, if there's been a previous packet wi= th a >>>>>> >>>>> certain TSval from that flow etc. >>>>>> >>>>> >>>>>> >>>>> Furthermore, if a flow is always processed on the same core (o= n both >>>>>> >>>>> ingress and egress) I think per-CPU maps may be a bit wasteful= on >>>>>> >>>>> memory. From my understanding the keys for per-CPU maps are st= ill >>>>>> >>>>> shared across all CPUs, it's just that each CPU gets its own v= alue. So >>>>>> >>>>> all CPUs will then have their own data for each flow, but it's= only the >>>>>> >>>>> CPU processing the flow that will have any relevant data for t= he flow >>>>>> >>>>> while the remaining CPUs will just have an empty state for tha= t flow. >>>>>> >>>>> Under the same assumption that packets within the same flow ar= e always >>>>>> >>>>> processed on the same core there should generally not be any >>>>>> >>>>> concurrency issues with having a global (non-per-CPU) either a= s packets >>>>>> >>>>> from the same flow cannot be processed concurrently then (and = thus no >>>>>> >>>>> concurrent access to the same value in the map). I am however = still >>>>>> >>>>> very unclear on if there's any considerable performance impact= between >>>>>> >>>>> global and per-CPU map versions if the same key is not accesse= d >>>>>> >>>>> concurrently. >>>>>> >>>>> >>>>>> >>>>> > > Right now, output >>>>>> >>>>> > > is just stubbed - I've still got to port the perfmap outpu= t code. Instead, >>>>>> >>>>> > > I'm dumping a bunch of extra data to the kernel debug pipe= , so I can see >>>>>> >>>>> > > roughly what the output would look like. >>>>>> >>>>> > > >>>>>> >>>>> > > With debug enabled and just logging I'm now getting about = 4.9 Gbits/sec on >>>>>> >>>>> > > single-stream iperf between two VMs (with a shaper VM in t= he middle). :-) >>>>>> >>>>> > >>>>>> >>>>> > Just FYI, that "just logging" is probably the biggest source= of >>>>>> >>>>> > overhead, then. What Simon found was that sending the data f= rom kernel >>>>>> >>>>> > to userspace is one of the most expensive bits of epping, at= least when >>>>>> >>>>> > the number of data points goes up (which is does as addition= al flows are >>>>>> >>>>> > added). >>>>>> >>>>> >>>>>> >>>>> Yhea, reporting individual RTTs when there's lots of them (you= may get >>>>>> >>>>> upwards of 1000 RTTs/s per flow) is not only problematic in te= rms of >>>>>> >>>>> direct overhead from the tool itself, but also becomes demandi= ng for >>>>>> >>>>> whatever you use all those RTT samples for (i.e. need to log, = parse, >>>>>> >>>>> analyze etc. a very large amount of RTTs). One way to deal wit= h that is >>>>>> >>>>> of course to just apply some sort of sampling (the -r/--rate-l= imit and >>>>>> >>>>> -R/--rtt-rate >>>>>> >>>>> > >>>>>> >>>>> > > So my question: how would you prefer to receive this data?= I'll have to >>>>>> >>>>> > > write a daemon that provides userspace control (periodic c= leanup as well as >>>>>> >>>>> > > reading the performance stream), so the world's kinda our = oyster. I can >>>>>> >>>>> > > stick to Kathie's original format (and dump it to a named = pipe, perhaps?), >>>>>> >>>>> > > a condensed format that only shows what you want to use, a= n efficient >>>>>> >>>>> > > binary format if you feel like parsing that... >>>>>> >>>>> > >>>>>> >>>>> > It would be great if we could combine efforts a bit here so = we don't >>>>>> >>>>> > fork the codebase more than we have to. I.e., if "upstream" = epping and >>>>>> >>>>> > whatever daemon you end up writing can agree on data format = etc that >>>>>> >>>>> > would be fantastic! Added Simon to Cc to facilitate this :) >>>>>> >>>>> > >>>>>> >>>>> > Briefly what I've discussed before with Simon was to have th= e ability to >>>>>> >>>>> > aggregate the metrics in the kernel (WiP PR [0]) and have a = userspace >>>>>> >>>>> > utility periodically pull them out. What we discussed was do= ing this >>>>>> >>>>> > using an LPM map (which is not in that PR yet). The idea wou= ld be that >>>>>> >>>>> > userspace would populate the LPM map with the keys (prefixes= ) they >>>>>> >>>>> > wanted statistics for (in LibreQOS context that could be one= key per >>>>>> >>>>> > customer, for instance). Epping would then do a map lookup i= nto the LPM, >>>>>> >>>>> > and if it gets a match it would update the statistics in tha= t map entry >>>>>> >>>>> > (keeping a histogram of latency values seen, basically). Sim= on's PR >>>>>> >>>>> > below uses this technique where userspace will "reset" the h= istogram >>>>>> >>>>> > every time it loads it by swapping out two different map ent= ries when it >>>>>> >>>>> > does a read; this allows you to control the sampling rate fr= om >>>>>> >>>>> > userspace, and you'll just get the data since the last time = you polled. >>>>>> >>>>> >>>>>> >>>>> Thank's Toke for summarzing both the current state and the pla= n going >>>>>> >>>>> forward. I will just note that this PR (and all my other work = with >>>>>> >>>>> ePPing/BPF-PPing/XDP-PPing/I-suck-at-names-PPing) will be more= or less >>>>>> >>>>> on hold for a couple of weeks right now as I'm trying to finis= h up a >>>>>> >>>>> paper. >>>>>> >>>>> >>>>>> >>>>> > I was thinking that if we all can agree on the map format, t= hen your >>>>>> >>>>> > polling daemon could be one userspace "client" for that, and= the epping >>>>>> >>>>> > binary itself could be another; but we could keep compatibil= ity between >>>>>> >>>>> > the two, so we don't duplicate effort. >>>>>> >>>>> > >>>>>> >>>>> > Similarly, refactoring of the epping code itself so it can b= e plugged >>>>>> >>>>> > into the cpumap-tc code would be a good goal... >>>>>> >>>>> >>>>>> >>>>> Should probably do that...at some point. In general I think it= 's a bit >>>>>> >>>>> of an interesting problem to think about how to chain multiple= XDP/tc >>>>>> >>>>> programs together in an efficent way. Most XDP and tc programs= will do >>>>>> >>>>> some amount of packet parsing and when you have many chained p= rograms >>>>>> >>>>> parsing the same packets this obviously becomes a bit wasteful= . In the >>>>>> >>>>> same time it would be nice if one didn't need to manually merg= e >>>>>> >>>>> multiple programs together into a single one like this to get = rid of >>>>>> >>>>> this duplicated parsing, or at least make that process of merg= ing those >>>>>> >>>>> programs as simple as possible. >>>>>> >>>>> >>>>>> >>>>> >>>>>> >>>>> > -Toke >>>>>> >>>>> > >>>>>> >>>>> > [0] https://github.com/xdp-project/bpf-examples/pull/59 >>>>>> >>>>> >>>>>> >>>>> N=C3=A4r du skickar e-post till Karlstads universitet behandla= r vi dina personuppgifter. >>>>>> >>>>> When you send an e-mail to Karlstad University, we will proces= s your personal data. >>>>>> >>>> >>>>>> >>>> _______________________________________________ >>>>>> >>>> LibreQoS mailing list >>>>>> >>>> LibreQoS@lists.bufferbloat.net >>>>>> >>>> https://lists.bufferbloat.net/listinfo/libreqos >>>>>> >>> >>>>>> >>> >>>>>> >>> >>>>>> >>> -- >>>>>> >>> Robert Chac=C3=B3n >>>>>> >>> CEO | JackRabbit Wireless LLC >>>>>> > >>>>>> > _______________________________________________ >>>>>> > LibreQoS mailing list >>>>>> > LibreQoS@lists.bufferbloat.net >>>>>> > https://lists.bufferbloat.net/listinfo/libreqos >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> This song goes out to all the folk that thought Stadia would work: >>>>>> https://www.linkedin.com/posts/dtaht_the-mushroom-song-activity-6981= 366665607352320-FXtz >>>>>> Dave T=C3=A4ht CEO, TekLibre, LLC >>>> >>>> _______________________________________________ >>>> LibreQoS mailing list >>>> LibreQoS@lists.bufferbloat.net >>>> https://lists.bufferbloat.net/listinfo/libreqos >>> >>> >>> >>> -- >>> Robert Chac=C3=B3n >>> CEO | JackRabbit Wireless LLC >>> _______________________________________________ >>> LibreQoS mailing list >>> LibreQoS@lists.bufferbloat.net >>> https://lists.bufferbloat.net/listinfo/libreqos > > _______________________________________________ > LibreQoS mailing list > LibreQoS@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/libreqos --=20 This song goes out to all the folk that thought Stadia would work: https://www.linkedin.com/posts/dtaht_the-mushroom-song-activity-69813666656= 07352320-FXtz Dave T=C3=A4ht CEO, TekLibre, LLC