Attendees
- peterlei@
- rrs@
- rscheff@
- tuexen@
Ongoing Short Term Projects
glebius@ asks whether it makes sense to improve the TCP timer precision. tuexen@ states that this is very useful for testing purposes. glebius@ will provide a patch to tuexen@ for testing and tuexen@ will provide feedback, if such a patch us useful for FreeBSD in general. This applies to the default stack only, not the the RACK or BBR stack, which uses HPTS for timers. Setting the sysctl variable kern.timecounter.alloweddeviation to zero allows the timers to run of very precisely, which is useful when running packetdrill. However, it affects the overall system performance.
At least for testing purposes (packetdrill) it would be good to have LRO support for tun interfaces. tuexen@ suggested to generalize LRO to not depend on an Ethernet header being present. gallatin@ prefers to not make the LRO code more complex, since it most likely will impact the performance. tjh@ has D37437 under review, which allows the tun interface to add an Ethernet header. tuexen@ will test this to see if it can also be used to enable LRO for the tun interface. This seems netmap specific. tuexen@ will consider to use tap interfaces in packetdrill.
D28822 improves PRR. rrs@ and tuexen@ will review. Will be committed after stable/14 is branched.
D39299 improves compliance to RFC 6675 with regard to the isLost variable. rrs@ and cc@ will review it. cc@ tested in Emulab. Will be committed after stable/14 is branched.
- BBLog is missing a man page. tuexen@ will write one.
On the current mailing list some build problems of CC modules using the TCP hooks were reported. D41010 will fix the builds. There is the question whether it should be possible to build the module also from the cc_cc_vegas directory. tuexen@ will ask imp@ if this should be supported or not.
rscheff@ reported a problem related to the dandling of RST ACK segments in the SYN_RECV state. tuexen@ will add tests to the tcp test suite and will work together with rscheff@ to fix the issue.
Ongoing Longer Term Projects
- It was discussed whether RACK and BBR can be build by default. RACK will be enabled in after stable/14 has been branched. It will be discussed with security@ and announced on mailing lists first.
- It was discussed that it would be a good idea to move the freebsd stack from ticks to micro seconds.
rscheff@ is improving AccECN code: D36303. rrs@ will review it and implement it for the rack stack.
D23230 is implementing ECN++. rrs@ will review it.
tuexen@ wants to write a tool which dumps the BBLog information of a TCP endpoint from a life system or a core. Using kvm_read() has drawbacks as glebius@ pointed out, using a python kgdb script may be an alternative. An alternative is to write a python kgdb script which pumps data into tcplog_dumper. This would allow to minimize code duplication. @glebius will try to work on this soon.
Next Meeting
27 July 2023 @ 1500 UTC