Document benchmarking CLI (#11246)

* Decrese default repeats

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Add benchmarking READMEs

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Update docs

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Update docs

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Update README

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Review fixes

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

Co-authored-by: parity-processbot <>
Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

substrate/utils/frame/benchmarking-cli/src/shared/README.md

@@ -0,0 +1,15 @@
+# Shared code
+
+Contains code that is shared among multiple sub-commands.
+
+## Arguments
+
+- `--mul` Multiply the result with a factor. Can be used to manually adjust for future chain growth.
+- `--add` Add a value to the result. Can be used to manually offset the results.
+- `--metric` Set the metric to use for calculating the final weight from the raw data. Defaults to `average`.
+- `--weight-path` Set the file or directory to write the weight files to.
+- `--db` The database backend to use. This depends on your snapshot.
+- `--pruning` Set the pruning mode of the node. Some benchmarks require you to set this to `archive`.
+- `--base-path` The location on the disk that should be used for the benchmarks. You can try this on different disks or even on a mounted RAM-disk. It is important to use the same location that will later-on be used to store the chain data to get the correct results.
+
+License: Apache-2.0