Date: Thu, 13 Oct 2022 19:02:00 -0400 From: Mark Saad <nonesuch@longcount.org> To: Wojciech Puchar <wojtek@puchar.net> Cc: freebsd-hackers@freebsd.org Subject: Re: is this FreeBSD problem or HP switch Message-ID: <CAMXt9NZzdRZHEPaiUGHh1rRDXjto%2BHUPK42r8pE4sVT6ahNZJw@mail.gmail.com> In-Reply-To: <586238fe-a9f-94b5-65b6-bc505551e9fb@puchar.net> References: <586238fe-a9f-94b5-65b6-bc505551e9fb@puchar.net>
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--000000000000d6580c05eaf27fef Content-Type: text/plain; charset="UTF-8" Wojciech There could be a lot going on here. I have used HP-2530's on HP DL360's running FreeBSD without many problems. They are store and forward switches , so they do buffer packets before sending them along. So it could be dropping some of them but that should be easy to discover by looking at the switch's interface and checking how many errors you have on each port . However the issue you describe is probably not a FreeBSD problem or Switch problem, but more of a how busy your computer A is. When you start to saturate a network card for either packets per second or bits per second the OS will have to deal with it by delaying the response of other traffic by one way or another. Imagine your computer A is running a web server and you are hammering it with 1Gb/s of traffic. The CPU on that server will also become busy handling the traffic and running the webserver. When you then send that same computer ICMP, another TCP session , UDP traffic etc. The Network card will be unable to process the traffic , as it's out of resources, or it could accept the traffic in and the cpu may not idle enough to pick the packets off the card and process them in a in a timely manner. I hope that helps. On Thu, Oct 13, 2022 at 6:48 PM Wojciech Puchar <wojtek@puchar.net> wrote: > i have HP-2530-24G switch in home and 3 VLANs. > there was no traffic on 2 of them, one vlan have full bandwitch traffic > from computer A to computer B - at 1000Mbit/s > At this time ping from computer C to computer A (computer C have 100Mbit/s > card) was random between 1 and 1000ms. > > Just limiting artifically speed to 950Mbit/s solved the problem. > > Is this because switch behaves that way or can it be a FreeBSD problem > (all computers runs FreeBSD) > > > > -- mark saad | nonesuch@longcount.org --000000000000d6580c05eaf27fef Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr"><div dir=3D"ltr"><div>Wojciech</div><div>=C2=A0=C2=A0 Ther= e could be a lot going on here. I have used HP-2530's on HP DL360's= running FreeBSD without many problems.</div><div>They are store and forwar= d switches , so they do buffer packets before sending them along. So it cou= ld be dropping some of them</div><div>but that should be easy to discover b= y looking at the switch's interface and checking how many errors you ha= ve on each port .</div><div>However the issue you describe is probably not = a FreeBSD problem or Switch problem, but more of a how busy your computer A= is. <br></div><div>When you start to saturate a network card for either pa= ckets per second or bits per second the OS will have to deal with it by del= aying</div><div>=C2=A0the response of other traffic by one way or another. = Imagine your computer A is running a web server and you are hammering it wi= th <br></div><div>1Gb/s of traffic. The CPU on that server will also become= busy handling the traffic and running the webserver. When you then send</d= iv><div>=C2=A0that same computer ICMP, another TCP session , UDP traffic et= c. The Network card will be unable to process the traffic , as it's out= <br></div><div>of resources, or it could accept the traffic in and the cpu= may not idle enough to pick the packets off the card and process them in a= <br></div><div>in a timely manner.=C2=A0 <br></div><div><br></div><div>I h= ope that helps. <br></div></div><br><div class=3D"gmail_quote"><div dir=3D"= ltr" class=3D"gmail_attr">On Thu, Oct 13, 2022 at 6:48 PM Wojciech Puchar &= lt;<a href=3D"mailto:wojtek@puchar.net">wojtek@puchar.net</a>> wrote:<br= ></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;= border-left:1px solid rgb(204,204,204);padding-left:1ex">i have HP-2530-24G= switch in home and 3 VLANs.<br> there was no traffic on 2 of them, one vlan have full bandwitch traffic <br= > from computer A to computer B - at 1000Mbit/s<br> At this time ping from computer C to computer A (computer C have 100Mbit/s = <br> card) was random between 1 and 1000ms.<br> <br> Just limiting artifically speed to 950Mbit/s solved the problem.<br> <br> Is this because switch behaves that way or can it be a FreeBSD problem <br> (all computers runs FreeBSD)<br> <br> <br> <br> </blockquote></div><br clear=3D"all"><br>-- <br><div dir=3D"ltr" class=3D"g= mail_signature">mark saad | <a href=3D"mailto:nonesuch@longcount.org" targe= t=3D"_blank">nonesuch@longcount.org</a><br></div></div> --000000000000d6580c05eaf27fef--
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