Robert Foley <robert.fo...@linaro.org> writes:
> From: "Emilio G. Cota" <c...@braap.org> > > This yields sizable scalability improvements, as the below results show. > > Host: Two Intel E5-2683 v3 14-core CPUs at 2.00 GHz (Haswell) > > Workload: Ubuntu 18.04 ppc64 compiling the linux kernel with > "make -j N", where N is the number of cores in the guest. > <snip> So my numbers running a aarch64 guest running pigz with an x86_64 host the gains start to tail off past -smp 12 but still seem to be showing some gain up to -smp 16 (the host has 24 cores): ./aarch64-softmmu/qemu-system-aarch64 -machine virt,graphics=on,gic-version=3,virtualization=on -cpu cortex-a53 -serial mon:stdio -nic user,model=virtio-net-pci,hostfwd=tcp::2222-:22 -device virtio-scsi-pci -device scsi-hd,drive=hd0 -blockdev driver=raw,node-name=hd0,discard=unmap,file.driver=host_device,file.filename=/dev/zvol/hackpool-0/debian-buster-arm64 -kernel ../../../linux.git/builds/arm64.nopreempt/arch/arm64/boot/Image -append "console=ttyAMA0 root=/dev/sda2 systemd.unit=benchmark-pigz.service" -display none -m 4096 -snapshot -smp $SMP | Command | Mean [s] | Min...Max [s] | |-----------------------------+------------------+------------------| | =$QEMU $QEMU_ARGS -smp 4= | 146.738 ± 62.272 | 43.861...246.139 | | =$QEMU $QEMU_ARGS -smp 5= | 33.984 ± 13.370 | 29.501...72.032 | | =$QEMU $QEMU_ARGS -smp 6= | 26.128 ± 0.189 | 25.837...26.475 | | =$QEMU $QEMU_ARGS -smp 7= | 23.459 ± 0.090 | 23.252...23.560 | | =$QEMU $QEMU_ARGS -smp 8= | 21.579 ± 0.117 | 21.418...21.764 | | =$QEMU $QEMU_ARGS -smp 9= | 20.163 ± 0.142 | 19.938...20.387 | | =$QEMU $QEMU_ARGS -smp 10= | 19.028 ± 0.106 | 18.877...19.183 | | =$QEMU $QEMU_ARGS -smp 11= | 18.166 ± 0.093 | 18.081...18.386 | | =$QEMU $QEMU_ARGS -smp 12= | 17.464 ± 0.067 | 17.383...17.614 | | =$QEMU $QEMU_ARGS -smp 13= | 16.928 ± 0.104 | 16.754...17.158 | | =$QEMU $QEMU_ARGS -smp 14= | 16.615 ± 0.188 | 16.486...17.105 | | =$QEMU $QEMU_ARGS -smp 15= | 16.344 ± 0.176 | 16.094...16.680 | | =$QEMU $QEMU_ARGS -smp 16= | 16.085 ± 0.215 | 15.869...16.623 | -- Alex Bennée
