This is a linux proof-of-concept system for the Virtualized Congestion Control system proposed in our paper [available at http://dl.acm.org/citation.cfm?id=2934889&CFID=653697983&CFTOKEN=87338481 ]. This patch is in the linux tcp stack itself and so is not in a hypervisor, as true vCC is. However, we have attempted to structure this patch such that it is "hypervisor-like" in the sense that the patch sits in the tcp input path at one location and modifies packets. There is a single entry point and a single exit point to the patch, in other words, and the location is chosen such that a virtual switch filter could modify packets in the same way. For convenience, this patch does take advantage of some of the exisiting state and packet processing in the tcp stack, but all of the facilities used would be straightforward to replicate in a hypervisor implementation and, in some cases, are in our ESXi vCC implementation.
The intention of this patch is to provide a proof-of-concept for vCC using the receive window throttling technique in order provide a ECN-aware underlay congestion control algorithm to a guest using an ECN-unaware congestion control algorithm. Note that, in this case, the guest congestion control is not actually ECN-unaware, but we simulate that for the purposes of this patch.
This patch provides receive-window-throttling-based ECN response to an ECN-unaware guest, starting with the first ECN seen and staying in congestion avoidance mode thereafter. As such, this patch does not include connection setup, slow start, fast-retransmit, or timeout handling; it's focus is on steady-state ECN response.
This is a patch on linux kernel version 3.19, which can be found by tag, release, or hash bfa76d49576599a4b9f9b7a71f23d73d6dcff735 at https://github.com/torvalds/linux . The release page, from which the source code can be downloaded as an archive, is available here: https://github.com/torvalds/linux/releases/tag/v3.19
To use this patch, clone torvalids/linux and
check out kernel version 3.19. Then apply
this patch (perhaps using git apply),
and build
(make; sudo make modules_install; sudo make install).
The experiments to demonstrate the capabilities of this patch and re-create the results from the paper can be found at https://github.com/aranb/vcc-exp
The homepage for vCC, with links to relevant repositories and the latest extended version of the paper, can be found here: http://webee.technion.ac.il/~isaac/vcc/