[iperf] update README

Signed-off-by: Dimitrios Stavrakakis <dimitrios.stavrakakis@intel.com>

iperf/README.md

@@ -5,26 +5,59 @@ recent version of `iperf` as of this writing (3.16).
 
 # Prerequisites
 
-`iperf` has no prerequisites.
+`iperf` has no prerequisites ([source](https://github.com/esnet/iperf?tab=readme-ov-file#prerequisites)).
 
-# Execution instructions
+# Building instructions
+
+## Building for Linux
+
+Run `make` in the root directory.
+
+## Building for SGX
 
-```sh
-# build iperf and the final manifest
-make SGX=1
+Run `make SGX=1` (non-debug) or `make SGX=1 DEBUG=1` (debug) in the root directory.
 
-# To run the original iperf server, use:
+# Execution instructions
+
+Run `iperf` server natively:
+```
 LD_LIBRARY_PATH=./install ./install/iperf3 -s
+```
 
-# To run the iperf server in non-SGX Gramine, use:
+Run `iperf` server in Gramine without SGX:
+```
 gramine-direct iperf3
+```
 
-# To run the iperf server in Gramine-SGX, use:
+Run `iperf` server in Gramine with SGX:
+```
 gramine-sgx iperf3
+```
 
-# To get measurements with the iperf client, run in another terminal:
+To get measurements with the `iperf` client, run in another terminal:
+```
 LD_LIBRARY_PATH=./install ./install/iperf3 -c localhost -p 5201
 ```
 
+# Useful iperf options
+## Generic options (both for server and client):
+- `-p, --port`: server port to listen on/connect to
+- `--forceflush`: force flushing output at every interval
+- `-d, --debug[=#]`: emit debugging output (optional "=" and debug level: 1-4. Default is 4 - all messages)
+
+## Server-specific options:
+- `-s, --server`: run in server mode
+- `-1, --one-off`: handle one client connection then exit
+- `--idle-timeout #`: restart idle server after # seconds in case it got stuck (default - no timeout)
+
+## Client-specific options:
+- `-c, --client <host>`: run in client mode, connecting to <host>
+- `-t, --time #`: time in seconds to transmit for (default 10 secs)
+- `-n, --bytes #[KMG]`: number of bytes to transmit (instead of -t)
+- `-P, --parallel #`: number of parallel client streams to run
+- `-N, --no-delay`: set TCP/SCTP no delay, disabling Nagle's Algorithm
+
 # Notes
-Tested in `Ubuntu 22.04.3 LTS`.
+- Tested in `Ubuntu 22.04.3 LTS`.
+- In the execution instructions, we use port `5201` for the client.
+This is the default port used by `iperf`.