From: Eric Dumazet <eric.dumazet@gmail.com>
To: Rick Jones <rick.jones2@hp.com>
Cc: Hal Murray <hmurray@megapathdsl.net>,
bloat <bloat@lists.bufferbloat.net>
Subject: Re: [Bloat] SO_SNDBUF and SO_RCVBUF
Date: Fri, 24 Apr 2015 11:41:17 -0700 [thread overview]
Message-ID: <1429900877.22254.133.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <553A6FF1.7090508@hp.com>
On Fri, 2015-04-24 at 09:31 -0700, Rick Jones wrote:
> > netperf -t TCP_STREAM" uses a default size of 16384 bytes per sendmsg.
>
> Under Linux at least, and only because that is the default initial value
> for SO_SNDBUF for a TCP socket (via tcp_wmem).
>
> More generally, the default send size used by netperf is the value of
> SO_SNDBUF for the data socket immediately after its creation.
>
Yeah, this looks odd.
Note that right after a connect() or accept(), getsocktop(SO_SNDBUF)
might be very different than the 'default=16384'
Otherwise, we could not even send the first 10 packets for IW10 from one
sendmsg(), or a single full packet on loopback interface (MTU=65536)
Anyway, 16384 bytes as default buffer size on netperf is fine.
next prev parent reply other threads:[~2015-04-24 18:41 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 [this message]
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
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