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Luca Miccio
0975bab5ea
Add a new command line parameter to configure Xen cache colors. These colors are dumped together with other coloring info. Benchmarking the VM interrupt response time provides an estimation of LLC usage by Xen's most latency-critical runtime task. Results on Arm Cortex-A53 on Xilinx Zynq UltraScale+ XCZU9EG show that one color, which reserves 64 KiB of L2, is enough to attain best responsiveness: - Xen 1 color latency: 3.1 us - Xen 2 color latency: 3.1 us Since this is the most common target for Arm cache coloring, the default amount of Xen colors is set to one. More colors are instead very likely to be needed on processors whose L1 cache is physically-indexed and physically-tagged, such as Cortex-A57. In such cases, coloring applies to L1 also, and there typically are two distinct L1-colors. Therefore, reserving only one color for Xen would senselessly partitions a cache memory that is already private, i.e. underutilize it. Signed-off-by: Luca Miccio <lucmiccio@gmail.com> Signed-off-by: Marco Solieri <marco.solieri@minervasys.tech> Signed-off-by: Carlo Nonato <carlo.nonato@minervasys.tech> Reviewed-by: Jan Beulich <jbeulich@suse.com>