Date: Tue, 30 Jul 2024 09:15:40 -0700 From: Alex Arslan <ararslan@comcast.net> To: mike tancsa <mike@sentex.net> Cc: freebsd-hackers@freebsd.org Subject: Re: Diagnosing virtual machine network issues Message-ID: <E72DA395-3C66-4520-B58B-31C19E7462A3@comcast.net> In-Reply-To: <4AB1C33B-DD93-4484-B63A-9FF8FE612B15@comcast.net> References: <FA265FAA-216D-4DCC-92C0-50017C17F7DE@comcast.net> <4a5a177a-5356-453c-8a09-f1d63d5d2e16@sentex.net> <4AB1C33B-DD93-4484-B63A-9FF8FE612B15@comcast.net>
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Some progress on this front... > On Jul 19, 2024, at 9:08=E2=80=AFAM, Alex Arslan = <ararslan@comcast.net> wrote: >=20 >> If it happens frequently and you think it might be the network, = perhaps try with the Intel em driver instead of the virtio network = driver ? I forgot to mention, we swapped the virtio network device to the Intel e1000 device but haven't observed any difference. I did manage to narrow down the issue to a more minimal reproducer, = which is just a simple request to the invalid domain using libcurl, but with a 30-second timeout. (The Julia code sets that timeout internally.) I = tried compiling the reproducer and running the executable wrapped with `time` separately in the FreeBSD VM and on the Linux host. In the VM, it = actually sits and waits out the 30 seconds then errors with a timeout, and `time` reports a real time of 30.289 seconds. On the host, it's instantaneous; the resolution failure is reported immediately. I then tried setting the timeout in the VM to 31 seconds, and it produces the expected resolution failure with a real time of 30.420 seconds. I don't understand what's going on here...
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