Re: kern/54645: Netbooting over a direct cable connection is unreliable

[Andreas Gustafsson <gson%gson.org@localhost>]

The following reply was made to PR kern/54645; it has been noted by GNATS.

From: Andreas Gustafsson <gson%gson.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/54645: Netbooting over a direct cable connection is unreliable
Date: Fri, 20 Mar 2020 11:05:58 +0200

 After replacing the client machine by a Dell PowerEdge R630 and the
 straight-through four-pair cable with a two-pair crossover cable,
 the issue remains, which seems consistent with my hypothesis 
 that the server side is at fault.
 
 Pinging the client shows sporadic duplicate packets, and most of them
 are duplicates of the 8th or 16th previous ping response, which seems
 consistent with my hypothesis of some kind of receive ring corruption
 in the server's bnx(4) driver.
 
 $ ping 10.169.1.2
 PING 10.169.1.2 (10.169.1.2): 56 data bytes
 64 bytes from 10.169.1.2: icmp_seq=0 ttl=254 time=0.811067 ms
 64 bytes from 10.169.1.2: icmp_seq=1 ttl=254 time=0.720762 ms
 [...some uneventful packets omitted...]
 64 bytes from 10.169.1.2: icmp_seq=42 ttl=254 time=0.685701 ms
 64 bytes from 10.169.1.2: icmp_seq=43 ttl=254 time=0.685701 ms
 64 bytes from 10.169.1.2: icmp_seq=44 ttl=254 time=0.655042 ms
 64 bytes from 10.169.1.2: icmp_seq=45 ttl=254 time=0.686330 ms
 64 bytes from 10.169.1.2: icmp_seq=46 ttl=254 time=0.686121 ms
 64 bytes from 10.169.1.2: icmp_seq=47 ttl=254 time=0.686610 ms
 64 bytes from 10.169.1.2: icmp_seq=48 ttl=254 time=0.674597 ms
 64 bytes from 10.169.1.2: icmp_seq=49 ttl=254 time=0.672781 ms
 64 bytes from 10.169.1.2: icmp_seq=50 ttl=254 time=0.774330 ms
 64 bytes from 10.169.1.2: icmp_seq=51 ttl=254 time=0.686959 ms
 64 bytes from 10.169.1.2: icmp_seq=44 DUP! ttl=254 time=8000.432877 ms
 64 bytes from 10.169.1.2: icmp_seq=53 ttl=254 time=0.687588 ms
 64 bytes from 10.169.1.2: icmp_seq=54 ttl=254 time=0.687098 ms
 64 bytes from 10.169.1.2: icmp_seq=55 ttl=254 time=0.732495 ms
 64 bytes from 10.169.1.2: icmp_seq=56 ttl=254 time=0.686610 ms
 64 bytes from 10.169.1.2: icmp_seq=57 ttl=254 time=0.759314 ms
 64 bytes from 10.169.1.2: icmp_seq=58 ttl=254 time=0.771327 ms
 64 bytes from 10.169.1.2: icmp_seq=59 ttl=254 time=0.715105 ms
 64 bytes from 10.169.1.2: icmp_seq=44 DUP! ttl=254 time=16000.308070 ms
 64 bytes from 10.169.1.2: icmp_seq=61 ttl=254 time=0.682769 ms
 64 bytes from 10.169.1.2: icmp_seq=62 ttl=254 time=0.719156 ms
 64 bytes from 10.169.1.2: icmp_seq=63 ttl=254 time=0.687238 ms
 64 bytes from 10.169.1.2: icmp_seq=64 ttl=254 time=0.672222 ms
 64 bytes from 10.169.1.2: icmp_seq=65 ttl=254 time=0.682838 ms
 64 bytes from 10.169.1.2: icmp_seq=66 ttl=254 time=0.745486 ms
 64 bytes from 10.169.1.2: icmp_seq=67 ttl=254 time=0.663702 ms
 64 bytes from 10.169.1.2: icmp_seq=68 ttl=254 time=0.683885 ms
 64 bytes from 10.169.1.2: icmp_seq=69 ttl=254 time=0.686120 ms
 64 bytes from 10.169.1.2: icmp_seq=70 ttl=254 time=0.687238 ms
 64 bytes from 10.169.1.2: icmp_seq=71 ttl=254 time=0.686051 ms
 64 bytes from 10.169.1.2: icmp_seq=72 ttl=254 time=0.685702 ms
 64 bytes from 10.169.1.2: icmp_seq=73 ttl=254 time=0.730539 ms
 64 bytes from 10.169.1.2: icmp_seq=74 ttl=254 time=0.686121 ms
 64 bytes from 10.169.1.2: icmp_seq=75 ttl=254 time=0.817423 ms
 64 bytes from 10.169.1.2: icmp_seq=76 ttl=254 time=0.770489 ms
 64 bytes from 10.169.1.2: icmp_seq=77 ttl=254 time=0.686330 ms
 64 bytes from 10.169.1.2: icmp_seq=78 ttl=254 time=0.731796 ms
 64 bytes from 10.169.1.2: icmp_seq=79 ttl=254 time=0.686540 ms
 64 bytes from 10.169.1.2: icmp_seq=80 ttl=254 time=0.686540 ms
 64 bytes from 10.169.1.2: icmp_seq=81 ttl=254 time=0.686680 ms
 64 bytes from 10.169.1.2: icmp_seq=74 DUP! ttl=254 time=8000.666077 ms
 64 bytes from 10.169.1.2: icmp_seq=83 ttl=254 time=0.687028 ms
 64 bytes from 10.169.1.2: icmp_seq=84 ttl=254 time=0.731518 ms
 64 bytes from 10.169.1.2: icmp_seq=85 ttl=254 time=0.539524 ms
 64 bytes from 10.169.1.2: icmp_seq=86 ttl=254 time=0.532470 ms
 ^C
 
 -- 
 Andreas Gustafsson, gson%gson.org@localhost