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([2607:fb10:7061:7fd::8fc7]) by smtp.gmail.com with ESMTPSA id p17sm4307512qtk.39.2019.02.24.04.03.23 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 24 Feb 2019 04:03:23 -0800 (PST) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\)) Subject: Re: DSACK From: Randall Stewart In-Reply-To: <58102EB5-6A5A-4BE1-ADEA-4EDCB56A39AE@freebsd.org> Date: Sun, 24 Feb 2019 07:03:22 -0500 Cc: "Scheffenegger, Richard" , "freebsd-transport@freebsd.org" Content-Transfer-Encoding: quoted-printable Message-Id: <328BFA58-EF05-473C-9DC0-05549E662213@netflix.com> References: <5ACAD39A-2A77-43BB-BE93-994C1C6C93AB@freebsd.org> <5AD822A0-06D7-44DB-AFB1-2453FD59A222@freebsd.org> <58102EB5-6A5A-4BE1-ADEA-4EDCB56A39AE@freebsd.org> To: Michael Tuexen X-Mailer: Apple Mail (2.3445.9.1) X-Rspamd-Queue-Id: 10F396ACB7 X-Spamd-Bar: --------------- X-Spamd-Result: default: False [-15.81 / 15.00]; TO_DN_EQ_ADDR_SOME(0.00)[]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+ip6:2607:f8b0:4000::/36]; MV_CASE(0.50)[]; RCVD_COUNT_THREE(0.00)[3]; DKIM_TRACE(0.00)[netflix.com:+]; MX_GOOD(-0.01)[cached: alt1.aspmx.l.google.com]; DMARC_POLICY_ALLOW(-0.50)[netflix.com,reject]; SUBJ_ALL_CAPS(0.38)[5]; NEURAL_HAM_SHORT(-1.00)[-0.997,0]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_LAST(0.00)[]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US]; MID_RHS_MATCH_FROM(0.00)[]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; R_DKIM_ALLOW(-0.20)[netflix.com:s=google]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-transport@freebsd.org]; TO_MATCH_ENVRCPT_SOME(0.00)[]; WHITELIST_DMARC(-7.00)[netflix.com:D:+]; RCVD_IN_DNSWL_NONE(0.00)[4.3.8.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.0.0.4.6.8.4.0.b.8.f.7.0.6.2.list.dnswl.org : 127.0.5.0]; IP_SCORE(-2.68)[ip: (-8.70), ipnet: 2607:f8b0::/32(-2.64), asn: 15169(-2.00), country: US(-0.07)]; WHITELIST_SPF_DKIM(-3.00)[netflix.com:d:+,netflix.com:s:+] X-BeenThere: freebsd-transport@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussions of transport level network protocols in FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 24 Feb 2019 12:03:26 -0000 I just don=E2=80=99t remember ever seeing code in the stack to do DSACK. I know I have added some small bits to be aware of DSACK coming in from other stacks in BBR and Rack, but it only does accounting and does not use the information.. nor does it generate any.. I have thought about doing it, but I have not placed a big priority on it=E2=80=A6. R > On Feb 24, 2019, at 7:01 AM, Michael Tuexen = wrote: >=20 >> On 24. Feb 2019, at 12:32, Randall Stewart wrote: >>=20 >> I don=E2=80=99t think I have ever seen FreeBSD emit a DSACK. Now = admittedly >> I have only paid close attention in current. But that spans even back >> into 11 days I think. >>=20 >> Hmm wonder if I have a 10 machine I can go back and look at :) > I tried to test on 10.4 yesterday, but packetdrill doesn't run that > well on 10.4 (missing pcap functions)... I'm not sure I want to = backport it. >=20 > Best regards > Michael >>=20 >> R >>=20 >>> On Feb 23, 2019, at 5:30 AM, Michael Tuexen = wrote: >>>=20 >>>> On 23. Feb 2019, at 11:28, Scheffenegger, Richard = wrote: >>>>=20 >>>>=20 >>>> Bin grad am flughafen und hab leider nur HEAD bei mir (und ein iso = von 10, wo ich grad versuch, das mit scapy zu checken). >>>>=20 >>>> Falls du schnell einen packetdrill gegen BSD11 ohne D18960 machen = kannst, und es da noch DSACKs raussendet, w=C3=A4re das toll! >>>>=20 >>>> Ich f=C3=BCrchte aber, das das schon l=C3=A4ngere Zeit kaputt ist - = da wir nun doch noch nicht D18960 drinnen haben, wie ich irrt=C3=BCmlich = dachte. >>> OK. I'll take a look. >>>=20 >>> Have a save trip! >>>=20 >>> Best regards >>> Michael >>>>=20 >>>>=20 >>>>=20 >>>> -----Original Message----- >>>> From: Michael Tuexen =20 >>>> Sent: Samstag, 23. Februar 2019 11:25 >>>> To: Scheffenegger, Richard >>>> Cc: freebsd-transport@freebsd.org >>>> Subject: Re: DSACK >>>>=20 >>>> NetApp Security WARNING: This is an external email. Do not click = links or open attachments unless you recognize the sender and know the = content is safe. >>>>=20 >>>>=20 >>>>=20 >>>>=20 >>>>> On 23. Feb 2019, at 10:29, Scheffenegger, Richard = wrote: >>>>>=20 >>>>> Hi, >>>>>=20 >>>>> A colleague pointed me to the stack (HEAD) no longer emitting = DSACK options a few days ago... >>>>>=20 >>>>> I was under the impression, that older versions of FreeBSD would = send out DSACKs for spurious duplicate packets. >>>>>=20 >>>>> But when I try this script against HEAD, regular cumulative ACKs = without DSACK blocks are showing up. >>>>>=20 >>>>> Currently bandwidth starved - but was that a conscious decision? = Or was me observing DSACKs never a thing? >>>> I would say if it is working in stable/11, but not in stable/12 and = head, it is a regression. >>>>=20 >>>> Best regards >>>> Michael >>>>>=20 >>>>> Thanks a lot, >>>>> Richard >>>>>=20 >>>>=20 >>>=20 >>> _______________________________________________ >>> freebsd-transport@freebsd.org mailing list >>> https://lists.freebsd.org/mailman/listinfo/freebsd-transport >>> To unsubscribe, send any mail to = "freebsd-transport-unsubscribe@freebsd.org" >>=20 >> ------ >> Randall Stewart >> rrs@netflix.com >>=20 >>=20 >>=20 >=20 ------ Randall Stewart rrs@netflix.com