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+zen-rapl
+
 # ---> C
 # Prerequisites
 *.d
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 # zen-rapl
 
-Advanced monitoring of core power and frequencies on AMD Zen/Epyc processors using MSR.
\ No newline at end of file
+Advanced monitoring of core power and frequencies on AMD Zen processors using MSR.
+
+This uses model-specific registers (MSRs) to read the running average power levels (RAPL) the processor.  It is designed to compliment the [Zenpower3 driver](https://github.com/koweda/zenpower3).
+
+The output has been formatted to resemble those from the `sensors` utility so scripts that use the output from that command can parse it the same.
+
+## Example output
+```
+zen3-rapl
+Package:       109.59 W
+Core_0:          4.50 W
+Core_1:          5.02 W
+Core_2:          4.38 W
+Core_3:          4.71 W
+Core_4:          3.60 W
+Core_5:          3.91 W
+Core_6:          3.42 W
+Core_7:          4.00 W
+Core_8:          1.20 W
+Core_9:          2.46 W
+Core_10:         2.26 W
+Core_11:         2.44 W
+Core_12:         0.97 W
+Core_13:         1.62 W
+Core_14:         0.08 W
+Core_15:         1.52 W
+Core_0_eff:   4.600 GHz
+Core_1_eff:   3.680 GHz
+Core_2_eff:   3.680 GHz
+Core_3_eff:   3.680 GHz
+Core_4_eff:   3.680 GHz
+Core_5_eff:   3.680 GHz
+Core_6_eff:   3.680 GHz
+Core_7_eff:   3.680 GHz
+Core_8_eff:   3.680 GHz
+Core_9_eff:   4.600 GHz
+Core_10_eff:  3.680 GHz
+Core_11_eff:  3.680 GHz
+Core_12_eff:  3.680 GHz
+Core_13_eff:  3.680 GHz
+Core_14_eff:  3.680 GHz
+Core_15_eff:  3.680 GHz
+```
+
+## Requirements
+* AMD family 17h or 19h processor (Zen, Zen2, Zen3)
+* MSR kernel module (`modprobe msr`)
+* Access to the MSR device files at `/dev/cpu/*/msr` (usually requires root)
+
+## Building
+1. `make`
+2. `sudo ./zen-rapl`
+
+## Acknowlegements
+Based upon some code from [Zenmonitor 3](https://github.com/jpr999/zenmonitor3)
+