Attendees
- glebius@
- rscheff@
- rrs@
- tuexen@
- cc@
Ongoing Short Term Projects
It was discussed whether the TCP_LOG socket option should be inherited from the listener. jtl@ said that this should be the case, but interaction with the sysctl-variable net.inet.tcp.bb.log_auto_ratio should be taken into account. The patch is under review: D38436.
netstat does not support reading connection information from a core file anymore. tuexen@ will document that in the man-page. This has been committed as D39610. A corresponding cleanup for the source code is under review: D39688.
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.
D39299 improves compliance to RFC 6675 with regard to the isLost variable. rrs@ and cc@ will review it.
While working on allowing BBLog being used as a replacement of trpt, tuexen@ figured out that trpt is broken in several ways in stable/13. tuexen@ will commit a fix by direct commits in the stable/13 branch and will add a note to the trpt man-page that trpt is deprecated and will be removed in FreeBSD 14. The change is under review: D39436.
tuexen@ will try to improve the error handling in PRU functions to allow the reporting of more error cases and put it up for review. glebius@ will review it and make sure it works with the recent changes in the inp/tcb area. A patch is under review: D39591. glebius@ suggests to move the constants from in_ktrace.h to a separate file. He will provide a patch and tuexen@ will review it and update D39591.
Make sysctl-variable net.inet.tcp.functions_default per vnet or fib? tuexen@ will implement the vnet support after rrs@ gets updates for stack swiching in. This was committed as D39516. If possible, it will be MFCed to stable/13.
- cc@ is planing to improve siftr.
- glebius@ is separating the tcpcbs and the inps. markj@ will then improve the handling of vnets.
Ongoing Longer Term Projects
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
04 May 2023 @ 1500 UTC