Re: [Bloat] The sad state of MP-TCP
Juliusz Chroboczek writes: >>> There should be a knob in the kernel to transparently replace TCP with >>> MP-TCP, but I couldn't find one. > >> There is, sorta. Specifically, a BPF hook that can override the protocol >> (added in kernel 6.6): >> >> https://lore.kernel.org/all/cover.1692147782.git.geliang.t...@suse.com/ > > So we're no longer doing sysctls, we're now monkey patching system > calls? I guess if it works for JavaScript, why shouldn't it work for > the kernel. If it helps you sleep at night, you can think of it more as a lisp machine than a javascript runtime ;) You're not the first to make the comparison, though: https://dl.acm.org/doi/abs/10.1145/3609021.3609306 -Toke ___ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat
Re: [Bloat] The sad state of MP-TCP
>> There should be a knob in the kernel to transparently replace TCP with >> MP-TCP, but I couldn't find one. > There is, sorta. Specifically, a BPF hook that can override the protocol > (added in kernel 6.6): > > https://lore.kernel.org/all/cover.1692147782.git.geliang.t...@suse.com/ So we're no longer doing sysctls, we're now monkey patching system calls? I guess if it works for JavaScript, why shouldn't it work for the kernel. -- Juliusz ___ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat
Re: [Bloat] The sad state of MP-TCP
On Tue, Apr 02, 2024 at 12:40:45PM +0200, Simon Leinen via Bloat wrote: > So all we need is a small modification to, say, liblzma, to make systemd > install that hook when calling sshd. Right? ;-) Too soon :P ___ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat
Re: [Bloat] The sad state of MP-TCP
Toke Høiland-Jørgensen via Bloat writes: > Juliusz Chroboczek via Bloat writes: >> There should be a knob in the kernel to transparently replace TCP with >> MP-TCP, but I couldn't find one. > There is, sorta. Specifically, a BPF hook that can override the protocol > (added in kernel 6.6): > https://lore.kernel.org/all/cover.1692147782.git.geliang.t...@suse.com/ So all we need is a small modification to, say, liblzma, to make systemd install that hook when calling sshd. Right? ;-) -- Simon. ___ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat
Re: [Bloat] The sad state of MP-TCP
Juliusz Chroboczek via Bloat writes: > Unfortunately, MP-TCP does not replace TCP in Linux, it's implemented as > a separate transport protocol. That means that in order to use MP-TCP, > every application needs to be patched to use PROT_MPTCP instead of > PROT_TCP. Go applications need to call SetMultipathTCP(true) on every > net.Conn and every net.Listener. > > There should be a knob in the kernel to transparently replace TCP with > MP-TCP, but I couldn't find one. There is, sorta. Specifically, a BPF hook that can override the protocol (added in kernel 6.6): https://lore.kernel.org/all/cover.1692147782.git.geliang.t...@suse.com/ -Toke ___ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat
[Bloat] The sad state of MP-TCP
Hi, For those of you who don't remember, MP-TCP is an extension to TCP that implements multipath, and can be used both for fast roaming (redundancy) and for bandwidth aggregation. MP-TCP is able to cross NATs, and it can reliably detect that TCP extensions are being corrupted by middleboxes and transparently fall back to plain TCP. MP-TCP is an IETF standard. MP-TCP is in the Linux kernel since 5.6, and it has good performance since 5.12 [1]. It's also in Apple's kernels (it's used by Siri for fast roaming). Unfortunately, MP-TCP does not replace TCP in Linux, it's implemented as a separate transport protocol. That means that in order to use MP-TCP, every application needs to be patched to use PROT_MPTCP instead of PROT_TCP. Go applications need to call SetMultipathTCP(true) on every net.Conn and every net.Listener. There should be a knob in the kernel to transparently replace TCP with MP-TCP, but I couldn't find one. And of course no applications are being patched. Ssh is probably the application which I'd be most keen to run over MP-TCP [2], but the patch is being blocked upstream [3]. For what it's worth, I've just added MP-TCP support to storrent [4], with a view to making it enabled by default, which means that all three storrent users will get MP-TCP out of the box. Dave, are you looking for a new crusade? [1] https://github.com/multipath-tcp/mptcp_net-next/wiki#changelog [2] http://blog.multipath-tcp.org/blog/html/2022/07/08/openssh.html [3] https://github.com/openssh/openssh-portable/pull/335 [4] https://github.com/jech/storrent/commit/c8d95c17f4227da77b97d5b7a9bdf289fea44aca -- Juliusz ___ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat
