Hi Sephe, On 02/20/13 13:37, Sepherosa Ziehau wrote: > On Wed, Feb 20, 2013 at 9:46 AM, Lawrence Stewart <lstew...@room52.net> wrote: >> *crickets chirping* >> >> Time to move this discussion forward... >> >> >> If any robust counter-arguments exist, now is the time for us to hear >> them. I haven't read anything thus far which convinces me that we should >> not provide knobs to tune our stack's dynamics. >> >> In the absence of any compelling counter-arguments, I would like to >> propose the following: >> >> - We rename the net.inet.tcp.experimental sysctl node introduced in >> r242266 for IW10 support to net.inet.tcp.nonstandard, and re-parent the >> initcwnd10 sysctl under this node.
I should also add that I think initcwnd10 should be changed to initcwnd and take the number of segments as a value. >> - We introduce a new net.inet.tcp.nonstandard.allowed sysctl variable >> and default it to 0. Only when it is changed to 1 will we allow starkly >> non standards compliant behaviour to be enabled in the stack. As a more >> complex but expressive alternative, we can make the sysctl take a bit >> mask or CSV string which specifies which non-standard options the sys >> admin permits (I'd prefer this as we can easily test non-standard >> options like IW10 in head without blanket enabling all non standard >> behaviour). To be clear, my proposal is that specifying an allowed option in net.inet.tcp.nonstandard.allowed would not enable it as the default on all connections, but would allow the per-application mechanism we define to set the option. Setting net.inet.tcp.nonstandard.option_x to 1 would enable the option as default for all connections. >> - We introduce a new net.inet.tcp.nonstandard.noidlereset sysctl >> variable, and use it to enable/disable window-reset-after-idle behaviour >> as proposed by John. >> >> - We don't introduce a TF_IGNOREIDLE sockopt, and instead introduce a >> more generic sockopt and/or mechanism for per-application tuning of all >> options which affect stack dynamics (both standard and non-standard >> options). I'm open to suggestions on what this could/should look like. > > Lawrence, > > A route metric? BTW, as for IW10, it could also become a route metric > (as proposed by the draft author's presentation > http://www.ietf.org/proceedings/79/slides/tcpm-0.pdf) Are you suggesting having the ability to set knobs as route metrics in addition to sysctl and a per-app mechanism? If so then I am very much in favour of this. Assuming an option has been allowed in net.inet.tcp.nonstandard.allowed, it should be able to be set by an application or on a route, perhaps with a precedence hierarchy of app request trumps route metric trumps system default setting? Cheers, Lawrence _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
