Hi Paul, Thanks for the response. I've collected more precise data for you.
> Please share the command line, how you start the GNU/Linux VM, and what > GNU/Linux distribution you use. I'll share the specific command lines with the results data below. For the distro, I'm using buildroot-2022.02. I started with the configs/qemu_x86_64_defconfig file. Kernel 5.15.18. It's also set up to bundle the cpio initramfs inside the kernel image, includes iperf3, and e1000 drivers. > Please be specific. What kind of laptop (CPU, …)? It's an old Lenovo x220 laptop. Intel Core i5-2520M. 2 hyperthreaded cores. 2.5GHz. 8GB memory. > How do you measure the transfer speed? I'm using iperf3. It's running on the Windows 10 host using MSYS2, like so: iperf3 -s And from the guest like so: iperf3 -c 10.0.2.2 Results: As a baseline, I ran iperf3 over localhost on the host machine. Both client and server were running from MSYS2 with iperf3 installed using pacman -S iperf3. Results: 1.37Gbits/sec For the remaining tests, I ran iperf from the guest to host like so: iperf3 -c 10.0.2.2 qemu-system-x86_64.txt -kernel bzImage -append "console=ttyS0" -nic user,e1000 45.1Mbits/sec qemu-system-x86_64.txt -kernel bzImage -append "console=ttyS0" -nic user,virtio 33.9Mbits/sec qemu-system-x86_64.txt -kernel bzImage -append "console=ttyS0" -nic user,e1000 -accel whpx 63.5Mbits/sec qemu-system-x86_64.txt -kernel bzImage -append "console=ttyS0" -nic user,virtio -accel whpx 83.4Mbits/sec qemu-system-x86_64.txt -kernel bzImage -append "console=ttyS0" -nic user,virtio -accel whpx -m 4096 -smp 4 63.9Mbits/sec Notes: * virtio+whpx is the fastest, but virtio without whpx is slower than e1000. * None of the tests are saturating the host CPU. In fact CPU usage according to Task Manager stays below ~20%. * I get fairly different results from run to run for the same test. As much as +/- 10Mbits/sec observed so far. * Apparently -cpu host doesn't work on Windows hosts? Thanks again, //anders On Tue, Apr 5, 2022, at 11:44 PM, Paul Menzel wrote: > Dear Anders, > > > Am 05.04.22 um 22:31 schrieb Anders Pitman: > > I'm trying to improve user networking performance, especially from a > > Windows 10 host, Linux guest. My goal is to get at least 100Mbps > > duplex. I'm hoping to be able to saturate a 1Gbps link. I need to > > avoid requiring any admin privileges, which is why I'm doing user > > networking instead of setting up a TAP device. > > Please share the command line, how you start the GNU/Linux VM, and what > GNU/Linux distribution you use. > > > Currently I'm seeing about 20-50Mbps on an older Windows 10 laptop. > > Please be specific. What kind of laptop (CPU, …)? > > How do you measure the transfer speed? > > > Enabling -accel whpx improves that significantly, but still not > > 1Gbps, and requires Windows Pro and extra steps for the user to > > enable virtualization. > > > > I have a few specific questions: > > > > * Is 1Gbps realistic with my desired setup? > > * Does virtio work with the slirp user networking? I can enable it, > > but I'm not sure it's making much difference. > > * Is there potential to improve upon slirp with a different user > > networking implementation? It seems like if you set up an ivshmem > > interface (similar to how Looking Glass works) you could get really > > efficient packet transfers. I was under the impression this is how > > slirp+virtio would work, but again I'm not seeing the hoped-for > > performance. > > > > If such a thing is possible but doesn't exist, I would be interested > > in working on it myself. I would appreciate any pointers on any > > additional resources to get started with this. > > I’d say it should be possible with not-too old hardware, but I never > tried it myself. > > > Kind regards, > > Paul >
