Unverified Commit 242b16a7 authored by Philip Taron's avatar Philip Taron Committed by GitHub
Browse files

runInLinuxVM: apply Qemu's vCPU limit (#386224)

parents ee2c1b83 64503c86

pkgs/build-support/vm/default.nix

+8 −2
Original line number Diff line number Diff line
@@ -247,11 +247,17 @@ rec { 
    eval "$preVM"



    if [ "$enableParallelBuilding" = 1 ]; then

      QEMU_NR_VCPUS=0

      if [ ''${NIX_BUILD_CORES:-0} = 0 ]; then

        QEMU_OPTS+=" -smp cpus=$(nproc)"

        QEMU_NR_VCPUS="$(nproc)"

      else

        QEMU_OPTS+=" -smp cpus=$NIX_BUILD_CORES"

        QEMU_NR_VCPUS="$NIX_BUILD_CORES"

      fi

      # qemu only supports 255 vCPUs (see error from `qemu-system-x86_64 -smp 256`)

      if [ "$QEMU_NR_VCPUS" -gt 255 ]; then

        QEMU_NR_VCPUS=255

      fi

      QEMU_OPTS+=" -smp cpus=$QEMU_NR_VCPUS"

    fi



    # Write the command to start the VM to a file so that the user can