From: Eric Dumazet <eric.dumazet@gmail.com>
To: Stephen Hemminger <stephen@networkplumber.org>,
David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Subject: Re: de-indirect TCP congestion control
Date: Mon, 12 Mar 2018 13:03:35 -0700 [thread overview]
Message-ID: <f3e43da6-e549-bad1-c75b-76bbf4fff216@gmail.com> (raw)
In-Reply-To: <20180312124813.3fa6b833@xeon-e3>
On 03/12/2018 12:48 PM, Stephen Hemminger wrote:
> On Mon, 12 Mar 2018 15:04:06 -0400 (EDT)
> David Miller <davem@davemloft.net> wrote:
>
>> From: Stephen Hemminger <stephen@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 ?
next prev parent reply other threads:[~2018-03-12 20:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-12 18:45 de-indirect TCP congestion control Stephen Hemminger
2018-03-12 19:04 ` David Miller
2018-03-12 19:48 ` Stephen Hemminger
2018-03-12 20:03 ` Eric Dumazet [this message]
2018-03-12 20:05 ` David Miller
2018-03-12 20:51 ` Stephen Hemminger
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