Update wiki may be better: `wrmsr 0xc0011020` only applies to one core on SMP system

I use multicore cpu, so when following wiki by wrmsr 0xc0011020, the scripts/zen_workaround.py --check will output 'Zen workaround not entirely enabled?'.

After viewing this issue and seeing where the zen_workaround.py emits the log , I knew where the problem is.

Updated: using wrmsr 0xc0011020 -a 0x46404000000000 with -a may be not allowable (this link also says about SMP, SMP can be checked by uname -a ) in grub, so maybe can use the following in shell rc (I use .bashrc):

# change 6404000000000 to original rdmsr value , 16 to thread num and 0x46404000000000 to expected wrmsr value
if [[ $(sudo rdmsr -a -x 0xc0011020 | grep ^6404000000000$ | wc -l) > 0 ]];then
        echo "write wrmsr"
        sudo wrmsr 0xc0011020 -a 0x46404000000000
fi

Review the Zen wiki instructions alongside scripts/zen_workaround.py --check and the linked issue comment explaining its output. Verify how wrmsr behaves on SMP systems and whether the proposed shell commands are supported; done means the wiki clearly documents the correct per-core procedure and its limitations.