Date: Fri, 21 Oct 2022 23:12:51 +0800 From: Zhenlei Huang <zlei.huang@gmail.com> To: "Cui, Cheng" <Cheng.Cui@netapp.com> Cc: Michael Tuexen <michael.tuexen@lurchi.franken.de>, freebsd-net@freebsd.org Subject: Re: Too aggressive TCP ACKs Message-ID: <E7BD2488-940B-42E5-8C53-F420DA8F2283@gmail.com> In-Reply-To: <MN2PR06MB6237E90881035621441597989D2D9@MN2PR06MB6237.namprd06.prod.outlook.com> References: <75D35F36-7759-4168-ADBA-C2414F5B53BC@gmail.com> <712641B3-5196-40CC-9B64-04637F16F649@lurchi.franken.de> <62A0DD30-B3ED-48BE-9C01-146487599092@gmail.com> <MN2PR06MB6237E90881035621441597989D2D9@MN2PR06MB6237.namprd06.prod.outlook.com>
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--Apple-Mail=_CE8B108F-F95C-4892-9C09-3F81D49101F6 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > On Oct 21, 2022, at 11:02 PM, Cui, Cheng <Cheng.Cui@netapp.com = <mailto:Cheng.Cui@netapp.com>> wrote: >=20 > You can also think about MacOS=E2=80=99s delayed ACK setup in default = is conservative. > =20 > https://developer.apple.com/forums/thread/716394 = <https://developer.apple.com/forums/thread/716394>I thinks that's a good = starting point. Thanks! > =20 > =20 > --=20 > Cheng Cui > =20 > From: owner-freebsd-net@freebsd.org = <mailto:owner-freebsd-net@freebsd.org> <owner-freebsd-net@freebsd.org = <mailto:owner-freebsd-net@freebsd.org>> on behalf of Zhenlei Huang = <zlei.huang@gmail.com <mailto:zlei.huang@gmail.com>> > Date: Friday, October 21, 2022 at 11:01 AM > To: Michael Tuexen <michael.tuexen@lurchi.franken.de = <mailto:michael.tuexen@lurchi.franken.de>> > Cc: freebsd-net@freebsd.org <mailto:freebsd-net@freebsd.org> = <freebsd-net@freebsd.org <mailto:freebsd-net@freebsd.org>> > Subject: Re: Too aggressive TCP ACKs >=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 > =20 > On Oct 21, 2022, at 10:34 PM, Michael Tuexen = <michael.tuexen@lurchi.franken.de = <mailto:michael.tuexen@lurchi.franken.de>> wrote: > =20 > On 21. Oct 2022, at 16:19, Zhenlei Huang <zlei.huang@gmail.com = <mailto:zlei.huang@gmail.com>> wrote: >=20 > Hi, >=20 > While I was repeating = https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D258755 = <https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D258755>, I observed = a > strange behavior. The TCP ACKs from FreeBSD host are too aggressive. >=20 > My setup is simple: > A B > [ MacOS ] <=3D=3D=3D=3D> [ FreeBSD VM ] > 192.168.120.1 192.168.12.134 (disable tso and lro) > While A <--- B, i.e. A as server and B as client, the packets rate = looks good. >=20 > One session on B: >=20 > root@:~ # iperf3 -c 192.168.120.1 -b 10m > Connecting to host 192.168.120.1, port 5201 > [ 5] local 192.168.120.134 port 54459 connected to 192.168.120.1 port = 5201 > [ ID] Interval Transfer Bitrate Retr Cwnd > [ 5] 0.00-1.00 sec 1.25 MBytes 10.5 Mbits/sec 0 257 = KBytes =20 > [ 5] 1.00-2.00 sec 1.25 MBytes 10.5 Mbits/sec 0 257 = KBytes =20 > [ 5] 2.00-3.00 sec 1.12 MBytes 9.44 Mbits/sec 0 257 = KBytes =20 > [ 5] 3.00-4.00 sec 1.25 MBytes 10.5 Mbits/sec 0 257 = KBytes =20 > [ 5] 4.00-5.00 sec 1.12 MBytes 9.44 Mbits/sec 0 257 = KBytes =20 > [ 5] 5.00-6.00 sec 1.25 MBytes 10.5 Mbits/sec 0 257 = KBytes =20 > [ 5] 6.00-7.00 sec 1.12 MBytes 9.44 Mbits/sec 0 257 = KBytes =20 > [ 5] 7.00-8.00 sec 1.25 MBytes 10.5 Mbits/sec 0 257 = KBytes =20 > [ 5] 8.00-9.00 sec 1.12 MBytes 9.44 Mbits/sec 0 257 = KBytes =20 > [ 5] 9.00-10.00 sec 1.25 MBytes 10.5 Mbits/sec 0 257 = KBytes =20 > - - - - - - - - - - - - - - - - - - - - - - - - - > [ ID] Interval Transfer Bitrate Retr > [ 5] 0.00-10.00 sec 12.0 MBytes 10.1 Mbits/sec 0 = sender > [ 5] 0.00-10.00 sec 12.0 MBytes 10.1 Mbits/sec = receiver >=20 > iperf Done. >=20 > Another session on B: >=20 > root@:~ # netstat -w 1 -I vmx0 > input vmx0 output > packets errs idrops bytes packets errs bytes colls > 0 0 0 0 0 0 0 0 > 0 0 0 0 0 0 0 0 > 342 0 0 22600 526 0 775724 0 > 150 0 0 9900 851 0 1281454 0 > 109 0 0 7194 901 0 1357850 0 > 126 0 0 8316 828 0 1246632 0 > 122 0 0 8052 910 0 1370780 0 > 109 0 0 7194 819 0 1233702 0 > 120 0 0 7920 910 0 1370780 0 > 110 0 0 7260 819 0 1233702 0 > 123 0 0 8118 910 0 1370780 0 > 109 0 0 7194 819 0 1233702 0 > 73 0 0 5088 465 0 686342 0 > 0 0 0 0 0 0 0 0 > 0 0 0 0 0 0 0 0 >=20 >=20 >=20 > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D >=20 >=20 > While A ---> B, i.e. A as client and B as server, the ACKs sent from B = looks strange. >=20 > Session on A: >=20 > % iperf3 -c 192.168.120.134 -b 10m > Connecting to host 192.168.120.134, port 5201 > [ 5] local 192.168.120.1 port 52370 connected to 192.168.120.134 port = 5201 > [ ID] Interval Transfer Bitrate > [ 5] 0.00-1.00 sec 1.25 MBytes 10.5 Mbits/sec =20= > [ 5] 1.00-2.00 sec 1.25 MBytes 10.5 Mbits/sec =20= > [ 5] 2.00-3.00 sec 1.12 MBytes 9.44 Mbits/sec =20= > [ 5] 3.00-4.00 sec 1.25 MBytes 10.5 Mbits/sec =20= > [ 5] 4.00-5.00 sec 1.12 MBytes 9.44 Mbits/sec =20= > [ 5] 5.00-6.00 sec 1.25 MBytes 10.5 Mbits/sec =20= > [ 5] 6.00-7.00 sec 1.12 MBytes 9.44 Mbits/sec =20= > [ 5] 7.00-8.00 sec 1.25 MBytes 10.5 Mbits/sec =20= > [ 5] 8.00-9.00 sec 1.12 MBytes 9.44 Mbits/sec =20= > [ 5] 9.00-10.00 sec 1.25 MBytes 10.5 Mbits/sec =20= > - - - - - - - - - - - - - - - - - - - - - - - - - > [ ID] Interval Transfer Bitrate > [ 5] 0.00-10.00 sec 12.0 MBytes 10.1 Mbits/sec = sender > [ 5] 0.00-10.00 sec 12.0 MBytes 10.1 Mbits/sec = receiver >=20 > iperf Done. >=20 > Session on B: >=20 > root@:~ # netstat -w 1 -I vmx0 > input vmx0 output > packets errs idrops bytes packets errs bytes colls > 0 0 0 0 0 0 0 0 > 0 0 0 0 0 0 0 0 > 649 0 0 960562 330 0 21800 0 > 819 0 0 1233702 415 0 27390 0 > 910 0 0 1370780 459 0 30294 0 > 819 0 0 1233702 415 0 27390 0 > 910 0 0 1370780 459 0 30294 0 > 910 0 0 1370780 460 0 30360 0 > 819 0 0 1233702 414 0 27324 0 > 910 0 0 1370780 460 0 30360 0 > 819 0 0 1233702 414 0 27324 0 > 910 0 0 1370780 460 0 30360 0 > 285 0 0 412287 147 0 9981 0 > 0 0 0 0 0 0 0 0 > 0 0 0 0 0 0 0 0 > 0 0 0 0 0 0 0 0 >=20 >=20 > The ACK packets replied from B (the FreeBSD VM) are too aggressive. = They are > about one half of TCP packets received from A. >=20 > I've tested with different bitrates, from 10m to 300m, all behave the = same. > Tested with baremetal FreeBSD 13.1 Box as B (with intel em driver), = the=20 > bitrates is 1g, also behaves the same. >=20 > Also tried different FreeBSD versions, 11.4, 12.3, stable/13 and = current/14 all=20 > behave the same. >=20 >=20 > My question is, is that the expected behavior of current default TCP = stack? > That is what I would expect. TCP (on FreeBSD) is acking every other = packet. This > is also what is specified. MacOS, at least newer versions, send less = ACKs. > Thanks for fast response! >=20 > My have old memories about SACK which helps TCP performance. This = behavior > seems odd from my mind. But those memories date back to 2008, that is = 14 years ago. > =20 > The current implementation of TCP stack in FreeBSD head is too = complexed for me. > Can you please point me the RFCs specifying this? So I can start over = with a quick glue. > =20 > Thanks! >=20 >=20 > Best regards > Michael >=20 >=20 >=20 >=20 > Best regards, > Zhenlei --Apple-Mail=_CE8B108F-F95C-4892-9C09-3F81D49101F6 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 <html><head><meta http-equiv=3D"Content-Type" content=3D"text/html; = charset=3Dutf-8"></head><body style=3D"word-wrap: break-word; = -webkit-nbsp-mode: space; line-break: after-white-space;" class=3D""><br = class=3D""><div><blockquote type=3D"cite" class=3D""><div class=3D"">On = Oct 21, 2022, at 11:02 PM, Cui, Cheng <<a = href=3D"mailto:Cheng.Cui@netapp.com" = class=3D"">Cheng.Cui@netapp.com</a>> wrote:</div><br = class=3D"Apple-interchange-newline"><div class=3D""><div = class=3D"WordSection1" style=3D"page: WordSection1; caret-color: rgb(0, = 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; = font-variant-caps: normal; font-weight: normal; letter-spacing: normal; = text-align: start; text-indent: 0px; text-transform: none; white-space: = normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; = text-decoration: none;"><div style=3D"margin: 0in; font-size: 10pt; = font-family: Calibri, sans-serif;" class=3D""><span style=3D"font-size: = 11pt;" class=3D"">You can also think about MacOS=E2=80=99s delayed ACK = setup in default is conservative.<o:p class=3D""></o:p></span></div><div = style=3D"margin: 0in; font-size: 10pt; font-family: Calibri, = sans-serif;" class=3D""><span style=3D"font-size: 11pt;" class=3D""><o:p = class=3D""> </o:p></span></div><div style=3D"margin: 0in; = font-size: 10pt; font-family: Calibri, sans-serif;" class=3D""><span = style=3D"font-size: 11pt;" class=3D""><a = href=3D"https://developer.apple.com/forums/thread/716394" style=3D"color: = blue; text-decoration: underline;" = class=3D"">https://developer.apple.com/forums/thread/716394</a></span></di= v></div></div></blockquote><div>I thinks that's a good starting = point.</div><div>Thanks!</div><br class=3D""><blockquote type=3D"cite" = class=3D""><div class=3D""><div class=3D"WordSection1" style=3D"page: = WordSection1; caret-color: rgb(0, 0, 0); font-family: Helvetica; = font-size: 12px; font-style: normal; font-variant-caps: normal; = font-weight: normal; letter-spacing: normal; text-align: start; = text-indent: 0px; text-transform: none; white-space: normal; = word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: = none;"><div style=3D"margin: 0in; font-size: 10pt; font-family: Calibri, = sans-serif;" class=3D""><span style=3D"font-size: 11pt;" class=3D""><o:p = class=3D""></o:p></span></div><div style=3D"margin: 0in; font-size: = 10pt; font-family: Calibri, sans-serif;" class=3D""><span = style=3D"font-size: 11pt;" class=3D""><o:p = class=3D""> </o:p></span></div><div style=3D"margin: 0in; = font-size: 10pt; font-family: Calibri, sans-serif;" class=3D""><span = style=3D"font-size: 11pt;" class=3D""><o:p = class=3D""> </o:p></span></div><div class=3D""><div class=3D""><div = class=3D""><div style=3D"margin: 0in; font-size: 10pt; font-family: = Calibri, sans-serif;" class=3D""><span style=3D"font-size: 11pt;" = class=3D"">-- <o:p = class=3D""></o:p></span></div></div></div></div><div style=3D"margin: = 0in; font-size: 10pt; font-family: Calibri, sans-serif;" class=3D""><span = style=3D"font-size: 11pt;" class=3D"">Cheng Cui</span><span = style=3D"font-size: 11pt;" class=3D""><o:p = class=3D""></o:p></span></div><div style=3D"margin: 0in; font-size: = 10pt; font-family: Calibri, sans-serif;" class=3D""><span = style=3D"font-size: 11pt;" class=3D""><o:p = class=3D""> </o:p></span></div><div style=3D"border-style: solid = none none; border-top-width: 1pt; border-top-color: rgb(181, 196, 223); = padding: 3pt 0in 0in;" class=3D""><p class=3D"MsoNormal" style=3D"margin: = 0in 0in 12pt; font-size: 10pt; font-family: Calibri, sans-serif;"><b = class=3D""><span style=3D"font-size: 12pt;" class=3D"">From:<span = class=3D"Apple-converted-space"> </span></span></b><span = style=3D"font-size: 12pt;" class=3D""><a = href=3D"mailto:owner-freebsd-net@freebsd.org" style=3D"color: blue; = text-decoration: underline;" = class=3D"">owner-freebsd-net@freebsd.org</a><span = class=3D"Apple-converted-space"> </span><<a = href=3D"mailto:owner-freebsd-net@freebsd.org" style=3D"color: blue; = text-decoration: underline;" = class=3D"">owner-freebsd-net@freebsd.org</a>> on behalf of Zhenlei = Huang <<a href=3D"mailto:zlei.huang@gmail.com" style=3D"color: blue; = text-decoration: underline;" class=3D"">zlei.huang@gmail.com</a>><br = class=3D""><b class=3D"">Date:<span = class=3D"Apple-converted-space"> </span></b>Friday, October 21, = 2022 at 11:01 AM<br class=3D""><b class=3D"">To:<span = class=3D"Apple-converted-space"> </span></b>Michael Tuexen <<a = href=3D"mailto:michael.tuexen@lurchi.franken.de" style=3D"color: blue; = text-decoration: underline;" = class=3D"">michael.tuexen@lurchi.franken.de</a>><br class=3D""><b = class=3D"">Cc:<span class=3D"Apple-converted-space"> </span></b><a = href=3D"mailto:freebsd-net@freebsd.org" style=3D"color: blue; = text-decoration: underline;" class=3D"">freebsd-net@freebsd.org</a><span = class=3D"Apple-converted-space"> </span><<a = href=3D"mailto:freebsd-net@freebsd.org" style=3D"color: blue; = text-decoration: underline;" class=3D"">freebsd-net@freebsd.org</a>><br= class=3D""><b class=3D"">Subject:<span = class=3D"Apple-converted-space"> </span></b>Re: Too aggressive TCP = ACKs<o:p class=3D""></o:p></span></p></div><table class=3D"MsoNormalTable"= border=3D"1" cellspacing=3D"0" cellpadding=3D"0" align=3D"left" = width=3D"200" style=3D"width: 150pt; background-color: rgb(0, 103, 197); = background-position: initial initial; background-repeat: initial = initial;"><tbody class=3D""><tr class=3D""><td nowrap=3D"" = style=3D"padding: 7.5pt;" class=3D""><div style=3D"margin: 0in; = font-size: 10pt; font-family: Calibri, sans-serif;" class=3D""><b = class=3D""><span style=3D"font-family: Arial, sans-serif; color: = yellow;" class=3D"">NetApp Security WARNING</span></b><span = style=3D"font-family: Arial, sans-serif; color: yellow;" class=3D"">: = This is an external email. Do not click links or open attachments unless = you recognize the sender and know the content is safe.<span = class=3D"Apple-converted-space"> </span></span><span = style=3D"font-size: 11pt;" class=3D""><o:p = class=3D""></o:p></span></div></td></tr></tbody></table><p = class=3D"MsoNormal" style=3D"margin: 0in 0in 12pt; font-size: 10pt; = font-family: Calibri, sans-serif;"><span style=3D"font-size: 11pt;" = class=3D""><br class=3D""><br class=3D""><o:p = class=3D""></o:p></span></p><div class=3D""><div class=3D""><div = class=3D""><div style=3D"margin: 0in; font-size: 10pt; font-family: = Calibri, sans-serif;" class=3D""><span style=3D"font-size: 11pt;" = class=3D""><o:p class=3D""> </o:p></span></div></div></div><div = class=3D""><blockquote style=3D"margin-top: 5pt; margin-bottom: 5pt;" = class=3D""><div class=3D""><div style=3D"margin: 0in; font-size: 10pt; = font-family: Calibri, sans-serif;" class=3D""><span style=3D"font-size: = 11pt;" class=3D"">On Oct 21, 2022, at 10:34 PM, Michael Tuexen <<a = href=3D"mailto:michael.tuexen@lurchi.franken.de" style=3D"color: blue; = text-decoration: underline;" = class=3D"">michael.tuexen@lurchi.franken.de</a>> wrote:<o:p = class=3D""></o:p></span></div></div><div style=3D"margin: 0in; = font-size: 10pt; font-family: Calibri, sans-serif;" class=3D""><span = style=3D"font-size: 11pt;" class=3D""><o:p = class=3D""> </o:p></span></div><div class=3D""><blockquote = style=3D"margin-top: 5pt; margin-bottom: 5pt; font-variant-caps: normal; = text-align: start; -webkit-text-stroke-width: 0px; word-spacing: 0px;" = class=3D""><div style=3D"margin: 0in; font-size: 10pt; font-family: = Calibri, sans-serif;" class=3D""><span style=3D"font-size: 9pt; = font-family: Helvetica;" class=3D"">On 21. Oct 2022, at 16:19, Zhenlei = Huang <<a href=3D"mailto:zlei.huang@gmail.com" style=3D"color: blue; = text-decoration: underline;" class=3D"">zlei.huang@gmail.com</a>> = wrote:<br class=3D""><br class=3D"">Hi,<br class=3D""><br class=3D"">While= I was repeating<span class=3D"Apple-converted-space"> </span><a = href=3D"https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D258755" = style=3D"color: blue; text-decoration: underline;" = class=3D"">https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D258755</a>,= I observed a<br class=3D"">strange behavior. The TCP ACKs from FreeBSD = host are too aggressive.<br class=3D""><br class=3D"">My setup is = simple:<br class=3D""> A = &n= bsp; &nbs= p; B<br class=3D""> [ = MacOS ] <=3D=3D=3D=3D> [ FreeBSD VM ]<br = class=3D"">192.168.120.1 = 192.168.= 12.134 (disable tso and lro)<br class=3D"">While A <--- B, i.e. A as = server and B as client, the packets rate looks good.<br class=3D""><br = class=3D"">One session on B:<br class=3D""><br class=3D"">root@:~ # = iperf3 -c 192.168.120.1 -b 10m<br class=3D"">Connecting to host = 192.168.120.1, port 5201<br class=3D"">[ 5] local 192.168.120.134 = port 54459 connected to 192.168.120.1 port 5201<br class=3D"">[ ID] = Interval = Transfer = Bitrate = Retr Cwnd<br = class=3D"">[ 5] 0.00-1.00 sec 1.25 = MBytes 10.5 Mbits/sec 0 257 = KBytes <br class=3D"">[ 5] = 1.00-2.00 sec 1.25 MBytes 10.5 = Mbits/sec 0 257 KBytes = <br class=3D"">[ 5] = 2.00-3.00 sec 1.12 MBytes 9.44 = Mbits/sec 0 257 KBytes = <br class=3D"">[ 5] = 3.00-4.00 sec 1.25 MBytes 10.5 = Mbits/sec 0 257 KBytes = <br class=3D"">[ 5] = 4.00-5.00 sec 1.12 MBytes 9.44 = Mbits/sec 0 257 KBytes = <br class=3D"">[ 5] = 5.00-6.00 sec 1.25 MBytes 10.5 = Mbits/sec 0 257 KBytes = <br class=3D"">[ 5] = 6.00-7.00 sec 1.12 MBytes 9.44 = Mbits/sec 0 257 KBytes = <br class=3D"">[ 5] = 7.00-8.00 sec 1.25 MBytes 10.5 = Mbits/sec 0 257 KBytes = <br class=3D"">[ 5] = 8.00-9.00 sec 1.12 MBytes 9.44 = Mbits/sec 0 257 KBytes = <br class=3D"">[ 5] = 9.00-10.00 sec 1.25 MBytes 10.5 Mbits/sec = 0 257 KBytes = <br class=3D"">- - - - - - - - - - - = - - - - - - - - - - - - - -<br class=3D"">[ ID] Interval = Transfer = Bitrate = Retr<br class=3D"">[ = 5] 0.00-10.00 sec 12.0 MBytes 10.1 = Mbits/sec 0 = se= nder<br class=3D"">[ 5] 0.00-10.00 sec = 12.0 MBytes 10.1 Mbits/sec = &n= bsp; receiver<br class=3D""><br class=3D"">iperf = Done.<br class=3D""><br class=3D"">Another session on B:<br class=3D""><br= class=3D"">root@:~ # netstat -w 1 -I vmx0<br = class=3D""> &nb= sp;input = vmx0 = output<br = class=3D""> packets errs idrops = bytes packets errs = bytes colls<br = class=3D""> 0 = 0 0 = 0 = 0 = 0 = 0 = 0<br = class=3D""> 0 = 0 0 = 0 = 0 = 0 = 0 = 0<br = class=3D""> 342 = 0 0 = 22600 = 526 0 = 775724 0<br = class=3D""> 150 = 0 0 = 9900 = 851 0 = 1281454 0<br = class=3D""> 109 = 0 0 = 7194 = 901 0 = 1357850 0<br = class=3D""> 126 = 0 0 = 8316 = 828 0 = 1246632 0<br = class=3D""> 122 = 0 0 = 8052 = 910 0 = 1370780 0<br = class=3D""> 109 = 0 0 = 7194 = 819 0 = 1233702 0<br = class=3D""> 120 = 0 0 = 7920 = 910 0 = 1370780 0<br = class=3D""> 110 = 0 0 = 7260 = 819 0 = 1233702 0<br = class=3D""> 123 = 0 0 = 8118 = 910 0 = 1370780 0<br = class=3D""> 109 = 0 0 = 7194 = 819 0 = 1233702 0<br = class=3D""> 73 = 0 0 = 5088 = 465 0 = 686342 0<br = class=3D""> 0 = 0 0 = 0 = 0 = 0 = 0 = 0<br = class=3D""> 0 = 0 0 = 0 = 0 = 0 = 0 = 0<br class=3D""><br class=3D""><br class=3D""><br = class=3D"">=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D<br class=3D""><br = class=3D""><br class=3D"">While A ---> B, i.e. A as client and B as = server, the ACKs sent from B looks strange.<br class=3D""><br = class=3D"">Session on A:<br class=3D""><br class=3D"">% iperf3 -c = 192.168.120.134 -b 10m<br class=3D"">Connecting to host 192.168.120.134, = port 5201<br class=3D"">[ 5] local 192.168.120.1 port 52370 = connected to 192.168.120.134 port 5201<br class=3D"">[ ID] Interval = Transfer = Bitrate<br class=3D"">[ 5] = 0.00-1.00 sec 1.25 MBytes 10.5 = Mbits/sec = &n= bsp; <br class=3D"">[ 5] = 1.00-2.00 sec 1.25 MBytes 10.5 = Mbits/sec = &n= bsp; <br class=3D"">[ 5] = 2.00-3.00 sec 1.12 MBytes 9.44 = Mbits/sec = &n= bsp; <br class=3D"">[ 5] = 3.00-4.00 sec 1.25 MBytes 10.5 = Mbits/sec = &n= bsp; <br class=3D"">[ 5] = 4.00-5.00 sec 1.12 MBytes 9.44 = Mbits/sec = &n= bsp; <br class=3D"">[ 5] = 5.00-6.00 sec 1.25 MBytes 10.5 = Mbits/sec = &n= bsp; <br class=3D"">[ 5] = 6.00-7.00 sec 1.12 MBytes 9.44 = Mbits/sec = &n= bsp; <br class=3D"">[ 5] = 7.00-8.00 sec 1.25 MBytes 10.5 = Mbits/sec = &n= bsp; <br class=3D"">[ 5] = 8.00-9.00 sec 1.12 MBytes 9.44 = Mbits/sec = &n= bsp; <br class=3D"">[ 5] = 9.00-10.00 sec 1.25 MBytes 10.5 Mbits/sec = &n= bsp; <br class=3D"">- - - - - - - - - - - - - - - = - - - - - - - - - -<br class=3D"">[ ID] Interval = Transfer = Bitrate<br class=3D"">[ 5] = 0.00-10.00 sec 12.0 MBytes 10.1 Mbits/sec = &n= bsp; sender<br class=3D"">[ 5] = 0.00-10.00 sec 12.0 MBytes 10.1 Mbits/sec = &n= bsp; receiver<br class=3D""><br class=3D"">iperf = Done.<br class=3D""><br class=3D"">Session on B:<br class=3D""><br = class=3D"">root@:~ # netstat -w 1 -I vmx0<br = class=3D""> &nb= sp;input = vmx0 = output<br = class=3D""> packets errs idrops = bytes packets errs = bytes colls<br = class=3D""> 0 = 0 0 = 0 = 0 = 0 = 0 = 0<br = class=3D""> 0 = 0 0 = 0 = 0 = 0 = 0 = 0<br = class=3D""> 649 = 0 0 = 960562 = 330 0 = 21800 0<br = class=3D""> 819 = 0 0 = 1233702 415 = 0 27390 = 0<br = class=3D""> 910 = 0 0 = 1370780 459 = 0 30294 = 0<br = class=3D""> 819 = 0 0 = 1233702 415 = 0 27390 = 0<br = class=3D""> 910 = 0 0 = 1370780 459 = 0 30294 = 0<br = class=3D""> 910 = 0 0 = 1370780 460 = 0 30360 = 0<br = class=3D""> 819 = 0 0 = 1233702 414 = 0 27324 = 0<br = class=3D""> 910 = 0 0 = 1370780 460 = 0 30360 = 0<br = class=3D""> 819 = 0 0 = 1233702 414 = 0 27324 = 0<br = class=3D""> 910 = 0 0 = 1370780 460 = 0 30360 = 0<br = class=3D""> 285 = 0 0 = 412287 = 147 0 = 9981 0<br = class=3D""> 0 = 0 0 = 0 = 0 = 0 = 0 = 0<br = class=3D""> 0 = 0 0 = 0 = 0 = 0 = 0 = 0<br = class=3D""> 0 = 0 0 = 0 = 0 = 0 = 0 = 0<br class=3D""><br class=3D""><br class=3D"">The = ACK packets replied from B (the FreeBSD VM) are too aggressive. They = are<br class=3D"">about one half of TCP packets received from A.<br = class=3D""><br class=3D"">I've tested with different bitrates, from 10m = to 300m, all behave the same.<br class=3D"">Tested with baremetal = FreeBSD 13.1 Box as B (with intel em driver), the<span = class=3D"apple-converted-space"> </span><br class=3D"">bitrates is = 1g, also behaves the same.<br class=3D""><br class=3D"">Also tried = different FreeBSD versions, 11.4, 12.3, stable/13 and current/14 = all<span class=3D"apple-converted-space"> </span><br = class=3D"">behave the same.<br class=3D""><br class=3D""><br class=3D"">My= question is, is that the expected behavior of current default TCP = stack?<o:p class=3D""></o:p></span></div></blockquote><div = style=3D"margin: 0in; font-size: 10pt; font-family: Calibri, = sans-serif;" class=3D""><span style=3D"font-size: 9pt; font-family: = Helvetica;" class=3D"">That is what I would expect. TCP (on FreeBSD) is = acking every other packet. This<br class=3D"">is also what is specified. = MacOS, at least newer versions, send less ACKs.</span><span = style=3D"font-size: 11pt;" class=3D""><o:p = class=3D""></o:p></span></div></div></blockquote><div class=3D""><div = style=3D"margin: 0in; font-size: 10pt; font-family: Calibri, = sans-serif;" class=3D""><span style=3D"font-size: 11pt;" class=3D"">Thanks= for fast response!<o:p class=3D""></o:p></span></div></div><div = style=3D"margin: 0in; font-size: 10pt; font-family: Calibri, = sans-serif;" class=3D""><span style=3D"font-size: 11pt;" class=3D""><br = class=3D"">My have old memories about SACK which helps TCP performance. = This behavior<o:p class=3D""></o:p></span></div></div><div class=3D""><div= style=3D"margin: 0in; font-size: 10pt; font-family: Calibri, = sans-serif;" class=3D""><span style=3D"font-size: 11pt;" class=3D"">seems = odd from my mind. But those <span style=3D"" class=3D"">memories = date back to 2008, that is 14 years ago.</span><o:p = class=3D""></o:p></span></div></div><div class=3D""><div style=3D"margin: = 0in; font-size: 10pt; font-family: Calibri, sans-serif;" class=3D""><span = style=3D"font-size: 11pt;" class=3D""><o:p = class=3D""> </o:p></span></div></div><div class=3D""><div = style=3D"margin: 0in; font-size: 10pt; font-family: Calibri, = sans-serif;" class=3D""><span style=3D"font-size: 11pt;" class=3D"">The = current implementation of TCP stack in FreeBSD head is too complexed for = me.<o:p class=3D""></o:p></span></div></div><div class=3D""><div = style=3D"margin: 0in; font-size: 10pt; font-family: Calibri, = sans-serif;" class=3D""><span style=3D"font-size: 11pt;" class=3D"">Can = you please point me the RFCs specifying this? So I can start over with a = quick glue.<o:p class=3D""></o:p></span></div></div><div class=3D""><div = style=3D"margin: 0in; font-size: 10pt; font-family: Calibri, = sans-serif;" class=3D""><span style=3D"font-size: 11pt;" class=3D""><o:p = class=3D""> </o:p></span></div></div><div class=3D""><div = style=3D"margin: 0in; font-size: 10pt; font-family: Calibri, = sans-serif;" class=3D""><span style=3D"font-size: 11pt;" = class=3D"">Thanks!<br class=3D""><br class=3D""><o:p = class=3D""></o:p></span></div><blockquote style=3D"margin-top: 5pt; = margin-bottom: 5pt;" class=3D""><div class=3D""><div style=3D"margin: = 0in; font-size: 10pt; font-family: Calibri, sans-serif;" class=3D""><span = style=3D"font-size: 9pt; font-family: Helvetica;" class=3D""><br = class=3D"">Best regards<br class=3D"">Michael<br style=3D"caret-color: = rgb(0, 0, 0); font-variant-caps: normal; text-align: start; = -webkit-text-stroke-width: 0px; word-spacing: 0px;" class=3D""><br = class=3D""></span><span style=3D"font-size: 11pt;" class=3D""><o:p = class=3D""></o:p></span></div><blockquote style=3D"margin-top: 5pt; = margin-bottom: 5pt;" class=3D""><div style=3D"margin: 0in; font-size: = 10pt; font-family: Calibri, sans-serif;" class=3D""><span = style=3D"font-size: 9pt; font-family: Helvetica;" class=3D""><br = class=3D""><br class=3D""><br class=3D"">Best regards,<br = class=3D"">Zhenlei</span></div></blockquote></div></blockquote></div></div= ></div></div></blockquote></div><br class=3D""></body></html>= --Apple-Mail=_CE8B108F-F95C-4892-9C09-3F81D49101F6--
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