netdev - Re: [PATCH RFC net-next 00/11] udp gso

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Message-ID: <66ce1fb6-120f-ae49-704a-69915b317c6b@gmail.com>
Date:   Wed, 18 Apr 2018 06:35:52 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Sowmini Varadhan <sowmini.varadhan@...cle.com>,
        Willem de Bruijn <willemdebruijn.kernel@...il.com>
Cc:     "Samudrala, Sridhar" <sridhar.samudrala@...el.com>,
        Network Development <netdev@...r.kernel.org>,
        Willem de Bruijn <willemb@...gle.com>
Subject: Re: [PATCH RFC net-next 00/11] udp gso



On 04/18/2018 05:31 AM, Sowmini Varadhan wrote:
> 
> I went through the patch set and the code looks fine- it extends existing
> infra for TCP/GSO to UDP.
> 
> One thing that was not clear to me about the API: shouldn't UDP_SEGMENT
> just be automatically determined in the stack from the pmtu? Whats
> the motivation for the socket option for this? also AIUI this can be
> either a per-socket or a per-packet option?
> 
> However, I share Sridhar's concerns about the very fundamental change
> to UDP message boundary semantics here.  

There is no change at all.

This will only be used as a mechanism to send X packets of same size.

So instead of X system calls , one system call.

One traversal of some expensive part of the host stack.

The content on the wire should be the same.