Date: Tue, 30 Jul 2024 15:27:53 -0500 From: Jason Bacon <bacon4000@gmail.com> To: Alex Arslan <ararslan@comcast.net>, mike tancsa <mike@sentex.net> Cc: freebsd-hackers@freebsd.org Subject: Re: Diagnosing virtual machine network issues Message-ID: <799c7a15-52b8-4b44-bcbd-5ab6a3ef97a6@gmail.com> In-Reply-To: <E72DA395-3C66-4520-B58B-31C19E7462A3@comcast.net> References: <FA265FAA-216D-4DCC-92C0-50017C17F7DE@comcast.net> <4a5a177a-5356-453c-8a09-f1d63d5d2e16@sentex.net> <4AB1C33B-DD93-4484-B63A-9FF8FE612B15@comcast.net> <E72DA395-3C66-4520-B58B-31C19E7462A3@comcast.net>
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On 7/30/24 11:15, Alex Arslan wrote: > Some progress on this front... > >> On Jul 19, 2024, at 9:08 AM, Alex Arslan <ararslan@comcast.net> wrote: >> >>> 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... > Can you provide more context? I'm not seeing earlier messages anywhere in my email folders. Is this a Qemu issue? Coincidentally, I'm experimenting with FreeBSD under Qemu on my Mac Mini M1 and seeing about 93 mbits/sec in iperf, regardless of the NIC configured. ( VM to bare metal host ) Bare metal to bare metal shows 930 mbits/sec. -- Life is a game. Play hard. Play fair. Have fun.
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