From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tremer To: development@lists.ipfire.org Subject: Re: Introducing fireperf Date: Thu, 04 Feb 2021 16:48:36 +0000 Message-ID: <082ACED3-5396-479B-AB43-20BEC1A3D317@ipfire.org> In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="===============4284746020329777494==" List-Id: --===============4284746020329777494== Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Hi, Sorry if I came across a wrong way. I just didn=E2=80=99t know what to say apart from that it is of course possib= le. According to German law, it is illegal to create and distribute something= colloquially called =E2=80=9Chacker tools=E2=80=9D. I do not think that this= falls under it in that sense that a frying pan is not classified as a murder= weapon although it could be used as one. Potentially I would see this as a good tool to find out when a load-balancer = collapses because of the sheer amount of new connections being opened. Apache= Benchmark could do the same - although I do not know how efficient it is wit= h the whole HTTP protocol layer. -Michael > On 4 Feb 2021, at 16:36, Tom Rymes wrote: >=20 > Just curious. I know that there=E2=80=99s an inherent tension in this area,= and I wanted to prompt discussion, nothing more. >=20 > Tom >=20 >> On Feb 4, 2021, at 11:17 AM, Michael Tremer = wrote: >>=20 >> Hello, >>=20 >> Well, it is a network testing tool. They all can be used for some evil stu= ff, but so can be ping(8). >>=20 >> I was thinking about this during development, but I am not sure what could= be done to prevent this. >>=20 >> -Michael >>=20 >>> On 4 Feb 2021, at 16:16, Tom Rymes wrote: >>>=20 >>> Michael, >>>=20 >>> Any concerns that this could be used for evil? >>>=20 >>> Tom >>>=20 >>>> On Feb 4, 2021, at 10:57 AM, Michael Tremer wrote: >>>>=20 >>>> Hello all y=E2=80=99all, >>>>=20 >>>> I would like to introduce a small side-project I have been working on ca= lled fireperf. >>>>=20 >>>> It is a networking benchmarking tool which I have written to debug some = issues with IPFire on AWS and I thought this would be very useful for others,= too. >>>>=20 >>>>=20 >>>> A bit of a backstory >>>>=20 >>>> Everyone probably knows iperf and its newer brother iperf3 and has used = them. They can do bandwidth tests and usually should be quite good at then. U= nfortunately they are reaching their limits quite early. In my environment I = had at least a 5 GBit/s connection between my two machines and I wanted to cr= eate lots and lots of connections to stress-test the connection tracking. >>>>=20 >>>> This was unfortunately not possible with either of them, because iperf i= s starting a thread per connection and iperf3 limits its connections to 128 p= er process. In both cases this simply did not scale because my goal was to cr= eate connections in the 6 figures or more range. I simply ran out of memory. >>>>=20 >>>> Another issue that both sometimes have - and which I did not validate sp= ecifically in this case - is that they cannot generate enough traffic to satu= rate a link. However, I need to be able to simply trust that this is possible= as long as I have the CPU resources available. >>>>=20 >>>> Therefore a new tool was needed. >>>>=20 >>>> When I started writing fireperf, I did not intend to make it fit for thr= oughput tests, but since it was such a low-hanging fruit in the development p= rocess I added it, too. The original goal was simply to open a number of conn= ections (at least hundreds of thousands) and keep them open or let me know wh= en this is no longer possible. >>>>=20 >>>> Since I knew I was working on IPFire, I started to take advantage of Lin= ux=E2=80=99 modern APIs and try to delegate as much work as possible to the k= ernel. Especially since the whole Meltdown/Spectre debacle, sending data betw= een the kernel and userland is slow, and the less work I have to do in the us= er land, the more time I can spend on other things. >>>>=20 >>>> Therefore I use epoll() to let the kernel tell me when a socket is ready= to accept data and when something has happened and the connection broke down= . I am using getrandom() to get random data to send and I use timerfd to regu= larly notify me when to print some statistics. Therefore this application is = not very easily portable (it wasn=E2=80=99t an original design goal), but I a= m sure that there are some alternatives available if someone were to port thi= s to another OS. >>>>=20 >>>> iperf3 - the most efficient one I knew - used up all of my 8GB of memory= on my test system when started multiple times to create about 10k connection= s. Fireperf uses a few hundreds of kilobytes with tens of thousands of open c= onnections. In fact, it does not keep any state about the connections and the= refore uses the same amount of memory no matter how many connections are open= . The kernel will use some memory though, but I could not measure how much. >>>>=20 >>>> Without saturating my processor I can saturate any network link that I c= ould test up to 10 GBit/s. CPU usage normally is less than 10% and fireperf k= nows a mode (=E2=80=94k) in which it won=E2=80=99t send any data, but only ke= ep the connections open and regularly let the kernel (again, because I am a l= azy developer) send some keep alive packets. That way, it uses next to no CPU= resources while still generating a lot of stress for the network. >>>>=20 >>>> So here it is, my new tool. I hope someone finds this useful. >>>>=20 >>>> It is nice and tiny and everything comes in one binary file which only d= epends on the C standard library. >>>>=20 >>>> Sources are available on our Git server as usual: >>>>=20 >>>> https://git.ipfire.org/?p=3Dfireperf.git;a=3Dsummary >>>>=20 >>>> I tagged release number 0.1.0 and I will push a patch into next very soo= n. There are also Debian packages available if you want to give fireperf a tr= y on Debian: >>>>=20 >>>> deb https://packages.ipfire.org/fireperf buster/ >>>> deb-src https://packages.ipfire.org/fireperf buster/ >>>>=20 >>>> Replace buster with bullseye or sid if you are on those and do not forge= t to import the key: >>>>=20 >>>> curl https://packages.ipfire.org/79842AA7CDBA7AE3-pub.asc | apt-key add - >>>>=20 >>>> Documentation in form of a man-page is available here: >>>>=20 >>>> https://man-pages.ipfire.org/fireperf/fireperf.html >>>>=20 >>>> It would be great, if fireperf would become a great tool to benchmark IP= Fire. We definitely could do better in this department and hopefully gain bet= ter insights on any regressions in performance, or if certain hardware is bet= ter than other. I suppose throughput is not everything and fireperf should be= able to help us measure other factors, too. >>>>=20 >>>> -Michael >>>=20 >>=20 >=20 --===============4284746020329777494==--