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From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Hal Murray <hmurray@megapathdsl.net>,
	bloat <bloat@lists.bufferbloat.net>
Subject: Re: [Bloat] SO_SNDBUF and SO_RCVBUF
Date: Thu, 23 Apr 2015 00:11:54 +0200	[thread overview]
Message-ID: <20150422221154.GB31348@sesse.net> (raw)
In-Reply-To: <1429738979.18561.150.camel@edumazet-glaptop2.roam.corp.google.com>

On Wed, Apr 22, 2015 at 02:42:59PM -0700, Eric Dumazet wrote:
> Sorry, I do not understand you.
> 
> The nice thing about TCP_NOTSENT_LOWAT is that you no longer have to
> care about choosing the 'right SO_SNDBUF'
> 
> It is still CC responsibility to choose/set cwnd, but you hadn't set an
> artificial cap on cwnd.
> 
> You control the amount of 'unsent data' per socket.
> 
> If you set a low limit, application might have to issue more send()
> calls and get more EPOLLOUT events.
> 
> This also means that if you get an abort / eof, you no longer have a
> huge unsent queue that TCP API does not allow to cancel.
> 
> https://insouciant.org/tech/prioritization-only-works-when-theres-pending-data-to-prioritize/

So this URL is basically what I said; you need to have data to prioritize
between for this to be useful. If you just want to send a simple file
(and aborts in HTTP/1.1 basically don't really exist), it doesn't really
matter if you have a huge backlog or not.

So I'm sure it's useful for HTTP/2 or SPDY, but that's already pretty
advanced functionality.

/* Steinar */
-- 
Homepage: http://www.sesse.net/

      parent reply	other threads:[~2015-04-22 22:12 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-22 19:10 Hal Murray
2015-04-22 19:26 ` Rick Jones
2015-04-22 19:28 ` Dave Taht
2015-04-22 21:02   ` Eric Dumazet
2015-04-22 21:05     ` Rick Jones
2015-04-22 21:46       ` Eric Dumazet
2015-04-22 22:20         ` Simon Barber
2015-04-22 23:08           ` Eric Dumazet
2015-04-24  4:37       ` Dave Taht
2015-04-24  4:40         ` Dave Taht
2015-04-24 13:50           ` Eric Dumazet
2015-04-24 14:34             ` Dave Taht
2015-04-24 16:31             ` Rick Jones
2015-04-24 18:41               ` Eric Dumazet
2015-04-24  5:23         ` Eric Dumazet
2015-04-22 21:07     ` Steinar H. Gunderson
2015-04-22 21:42       ` Eric Dumazet
2015-04-22 21:47         ` Dave Taht
2015-04-22 22:11         ` Steinar H. Gunderson [this message]

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