From: Eric Dumazet <eric.duma...@gmail.com> Date: Mon, 12 Mar 2018 13:03:35 -0700
> > > On 03/12/2018 12:48 PM, Stephen Hemminger wrote: >> On Mon, 12 Mar 2018 15:04:06 -0400 (EDT) >> David Miller <da...@davemloft.net> wrote: >> >>> From: Stephen Hemminger <step...@networkplumber.org> >>> Date: Mon, 12 Mar 2018 11:45:52 -0700 >>> >>>> Since indirect calls are expensive, and now even more so, perhaps we >>>> should figure out >>>> a way to make the default TCP congestion control hooks into direct >>>> calls. >>>> 99% of the users just use the single CC module compiled into the >>>> kernel. >>> >>> Who is this magic user with only one CC algorithm enabled in their >>> kernel? I want to know who this dude is? >>> >>> I don't think it's going to help much since people will have I think >>> at least two algorithms compiled into nearly everyone's tree. >>> >>> Distributions will enable everything. >>> >>> Google is going to have at least two algorithms enabled. >>> >>> etc. etc. etc. >>> >>> Getting rid of indirect calls is a fine goal, but the precondition you >>> are mentioning to achieve this doesn't seem practical at all. >> What I meant is that kernels with N congestion controls, almost all >> traffic >> uses the default So that path can be optimized. The example I gave >> would >> have all the others doing the same indirect call. > > I do not understand. What is default_tcp_ops anyway ? > > How changes to /proc/sys/net/ipv4/tcp_congestion_control will impact > this ? I'm also confused what is being suggested exactly and how this can work. :-)
