Date: Tue, 30 Jul 2024 14:11:55 -0700 From: Alex Arslan <ararslan@comcast.net> To: Jason Bacon <bacon4000@gmail.com> Cc: mike tancsa <mike@sentex.net>, freebsd-hackers@freebsd.org Subject: Re: Diagnosing virtual machine network issues Message-ID: <0747ED5F-2ED6-461C-9C0B-CFD0EE480D82@comcast.net> In-Reply-To: <799c7a15-52b8-4b44-bcbd-5ab6a3ef97a6@gmail.com> 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> <799c7a15-52b8-4b44-bcbd-5ab6a3ef97a6@gmail.com>
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> Can you provide more context? I'm not seeing earlier messages anywhere in my email folders. Is this a Qemu issue? The original message is from just over a month ago, archived here: https://lists.freebsd.org/archives/freebsd-hackers/2024-June/003378.html Basically, we have FreeBSD 13.2 VMs running under KVM on a Linux machine. Some code is using libcurl to make a request to an invalid domain and is testing that the error is a resolution failure. This test passes on all platforms except specifically in these FreeBSD VMs; I can't reproduce locally on FreeBSD. That made me think that there's an issue with how the VM was set up, prompting the original message and discussion. Then what I recently found was that we set a 30-second timeout for the libcurl request, which FreeBSD hits in the VM, as it evidently spends a full 30 seconds attempting to resolve the host, while e.g. Linux reports a resolution failure immediately. > 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. That's interesting, can you show how you did that? I'm not familiar with iperf (or most things in the realm of networking). Do you know why it's so much slower?
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