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From: "Robert N. M. Watson" <rwatson@FreeBSD.org>
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To: Slawa Olhovchenkov <slw@zxy.spb.ru>
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Cc: Lev Serebryakov <lev@FreeBSD.org>, freebsd-arch@freebsd.org
Subject: Re: FreeBSD problems and preliminary ways to solve
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On 19 Aug 2011, at 10:05, Slawa Olhovchenkov wrote:

>> Is the issue here that FreeBSD is dropping more packes, or just that =
FreeBSD=20
>> is reporting that it drops packets?  Historically, we've returned =
ENOBUFS from=20
>> datagram sockets when the interface queue is overflowed, but some =
other=20
>> systems (most noticeably Linux) simply return success when they drop =
a packet=20
>> on an outgoing interface queue.  You can debate which is the better =
model, but=20
>> one impact is that sometimes people report errors on FreeBSD that =
they don't=20
>> see on Linux -- when actually, the same failure is present, we just =
allow the=20
>> application to learn about it.
>=20
> Historically, Linux on datagram (UDP) socket allow use select, FreeBSD
> -- don't allow. FreeBSD always report 'UDP socket ready to transmit'.
> And after try to send packet -- 'oops, ENOBUFS'.


And if you have two consumers sending UDP on Linux, they both get =
unreported 50% packet loss, to my understanding?

Robert=