How to simulate dual-core with the prebuilt linux image?

[zgliu799]

Hi,
I downloaded the prebuilt linux image and tried below command.
/sim.py --cpu-count 2
but the linux boot up show only 1 core.
Do I need to compile a new dts/dtb for dual-core linux-smp?
Thanks.

[Dolu1990]

Hi,

yes, you can normaly find a generated dts or dtb generated in somewere inside the build folder if i remember well.

[zgliu799]

Hi @Dolu1990 ,Thanks. Can you recommend which linux kernel version for vexriscv-smp? upstream or the version of pre-built image?
I want to build the kernel image and dts/dtb.

[Dolu1990]

I would say, you can stick with https://github.com/litex-hub/linux-on-litex-vexriscv/blob/master/buildroot/configs/litex_vexriscv_defconfig#L45

[zgliu799]

@Dolu1990 Do you suggest to use buildroot to build the image ? latest buildroot? Thanks.

[Dolu1990]

I would say, starting with https://github.com/litex-hub/linux-on-litex-vexriscv?tab=readme-ov-file#-generating-the-linux-binaries-optional

To get something up and running, and than mutating things (so small step by step iteration, to be sure to always have a functional system)

Latest buildroot should be fine.

[zgliu799]

I checked arty.v. There is only one CPU core:VexRiscvLitexSmpCluster_Cc2_Iw64Is8192Iy2_Dw64Ds8192Dy2_ITs4DTs4_Ldw128_Cdma_Ood_Hb1.
I think there should be at least 2 cores for linux-smp.

[Dolu1990]

When you change the parameters in the command line you use to run the SoC, it will automaticaly generate the corresponding VexRiscvLitexSmpCluster_...