How to find CPU Speed of zLinux

Need to find CPU Speed of zLinux.

The commands like cat /proc/cpuinfo and /usr/bin/cpufreq-info does not gave me the expected results.

/usr/bin/cpufreq-info prints the

....
analyzing CPU 0:
no or unknown cpufreq driver is active on this CPU
analyzing CPU 1:
no or unknown cpufreq driver is active on this CPU
analyzing CPU 2:

cat /proc/cpuinfo