Performance.md

Performance

Want to make Bang scream with speed while keeping your Arduino’s command-line domination on point? This page dives into performance factors for ! (shell), & (sketch uploads), and @ (macro) commands, ensuring your BANG("echo Hello") or BANG("&blink\n") runs like a champ. From serial speeds to host command latency, we’ll optimize Bang to stay lean for Arduino’s tight memory and maximize your project’s punch. Let’s rev up this beast!

Overview

• Purpose: Optimize Bang’s performance for Arduino and host interaction.
• Key Factors:
  • Serial-USB communication speed (baud rate).
  • Host command execution latency (! and @).
  • Sketch upload time (&).
  • Arduino memory usage.
• Goal: Balance speed and reliability for smooth operation.

Performance Factors

1. Serial Baud Rate

• Impact: Higher baud rates (e.g., 115200 vs. 38400) reduce command/response latency but may increase errors on some Arduino boards.
• Default: 38400 baud.
• Optimization:

  • Increase baud rate in sketch and arduino_exec.py:

    void setup() {
        Serial.begin(115200); // Faster than 38400
        while (!Serial) ;
    }

    Run arduino_exec.py with matching rate:

    sudo python3 arduino_exec.py -p /dev/cu.usbserial-00100 -b 115200

  • Test Stability: Some boards (e.g., Uno) may need lower rates (e.g., 57600) for reliability.

  • Tip: Match baud rates exactly to avoid communication errors.

2. Host Command Latency

• Impact: ! (shell) and @ (macro) commands depend on host shell or script execution speed.
• Optimization:

  • Use simple shell commands:

    BANG("echo Hello"); // Faster than complex scripts

  • Predefine macros for frequent commands:

    macros = {'weather': 'curl wttr.in?format=3'}  # In arduino_exec.py

    Then: BANG("@weather") (faster than BANG("curl wttr.in?format=3")).

  • Minimize host load: Close unnecessary apps to speed up command execution.

  • Cache results for repetitive macros if supported in arduino_exec.py.

3. Sketch Upload Time

• Impact: &sketch_name\n uploads involve compiling and flashing, which can take seconds.
• Optimization:

  • Use small sketches to reduce compile/upload time:

    // In blink.ino
    #include <Bang.h>
    Bang bang(Serial);
    void setup() {
        Serial.begin(38400);
        pinMode(13, OUTPUT);
    }
    void loop() {
        digitalWrite(13, HIGH);
        delay(1000);
        digitalWrite(13, LOW);
        delay(1000);
    }

  • Optimize arduino-cli:

    arduino-cli compile --fqbn arduino:avr:uno blink.ino --optimize-for-size

  • Precompile sketches if possible to reduce upload time.

  • Ensure fast host CPU and SSD for quicker compilation.

4. Arduino Memory Usage

• Impact: Bang’s lean design minimizes RAM usage, but complex sketches or many macros can strain Arduino’s memory.
• Optimization:

  • Use BANG_P for static commands to save RAM:

    BANG_P(PSTR("echo Hello")); // Stored in PROGMEM

  • Limit String usage:

    // Avoid
    String cmd = "curl https://example.com";
    BANG_S(cmd);
    // Prefer
    BANG("curl https://example.com");

  • Keep sketches minimal to leave room for Bang’s operations.

  • Monitor memory with Arduino IDE’s compiler output.

Testing Performance

• Measure Latency:

  • Add timing in sketch:

    unsigned long start = millis();
    BANG("echo Hello");
    Serial.print("Latency: ");
    Serial.println(millis() - start);

• Log Upload Time:

  • Modify arduino_exec.py:

    def compile_and_upload(sketch):
        start_time = time.time()
        # Upload logic
        print(f"Upload took {time.time() - start_time} seconds")

• Check Macro Speed:

  • Test @macro vs. direct ! commands:

    BANG("@weather"); // Should be faster than BANG("curl wttr.in?format=3")

Troubleshooting

• Slow Commands: Lower baud rate (e.g., 57600) or simplify commands.
• Upload Delays: Check arduino-cli logs or host CPU load.
• Memory Issues: Use BANG_P and minimize String objects.
• See Troubleshooting for more fixes.

Next Steps

• Check Testing for validating performance tweaks.
• Explore Examples for optimized sketches.
• See FAQ for performance questions.

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