Configure virtme/qemu with Numa support

This article describes how to start qemu / virtme with Numa support

Overview

When developing a new kernel feature or debugging a kernel functionality, it is sometimes necessary to have access to a NUMA machine. This is not always possible. An alternative to a physical NUMA machine is using qemu or the combination of qemu and virtme.

Starting virtme with NUMA support

To start virtme with NUMA support enabled, the following command can be used:

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virtme-run --kimg arch/x86_64/boot/bzImage                                    \
   --qemu-opts -m 8G -smp 4 -object memory-backend-ram,size=4G,id=m0          \
   -object memory-backend-ram,size=4G,id=m1                                   \
   -numa node,memdev=m0,cpus=0-1,nodeid=0                                     \
   -numa node,memdev=m1,cpus=2-3,nodeid=1

This assumes that the virtual machines is started with 8GB of memory and 4 CPU’s. It then creates 2 NUMA nodes each with 2 CPU’s and 4GB of memory. Other combinations are certainly possible by changing the corresponding parameters.