memory-rate.sh

memory-rate.sh

#!/bin/bash

# Configuration
INTERVAL=1             # Measurement interval in seconds
DURATION=60            # Number of measurements to take

# Automatically detect page size
PAGE_SIZE=$(getconf PAGESIZE)
echo "Detected page size: ${PAGE_SIZE} bytes"

# Function to read values from /proc/vmstat
read_vmstat() {
    local file="/proc/vmstat"
    pgmajfault=$(grep 'pgmajfault' $file | awk '{print $2}')
    pgpgin=$(grep 'pgpgin' $file | awk '{print $2}')
    pgpgout=$(grep 'pgpgout' $file | awk '{print $2}')

    echo "$pgmajfault $pgpgin $pgpgout"
}

# Array to store results
declare -a speeds

echo "Starting measurements every $INTERVAL second(s). Total: $DURATION measurements."

for ((i = 1; i <= DURATION; i++)); do
    read FIRST_FAULT FIRST_IN FIRST_OUT <<<$(read_vmstat)
    sleep $INTERVAL
    read LAST_FAULT LAST_IN LAST_OUT <<<$(read_vmstat)

    DELTA_FAULT=$((LAST_FAULT - FIRST_FAULT))
    DELTA_IN=$((LAST_IN - FIRST_IN))
    DELTA_OUT=$((LAST_OUT - FIRST_OUT))

    TOTAL_DELTA_PAGES=$((DELTA_IN + DELTA_OUT + DELTA_FAULT))
    DATA_BYTES=$((TOTAL_DELTA_PAGES * PAGE_SIZE))
    DATA_Mbps=$(echo "scale=2; ($DATA_BYTES * 8) / ($INTERVAL * 1000000)" | bc)

    speeds+=("$DATA_Mbps")
    echo "[$i] Dirty Page Bandwidth: ${DATA_Mbps} Mbps"
done

# Calculate statistics
sum=0
min=${speeds[0]}
max=0

for speed in "${speeds[@]}"; do
    sum=$(echo "$sum + $speed" | bc)
    (( $(echo "$speed > $max" | bc -l) )) && max=$speed
    (( $(echo "$speed < $min" | bc -l) )) && min=$speed
done

average=$(echo "scale=2; $sum / $DURATION" | bc)

# Summary output
echo "---------------------------------------------"
echo "SUMMARY:"
echo "  Minimum bandwidth:   $min Mbps"
echo "  Maximum bandwidth:   $max Mbps"
echo "  Average bandwidth:   $average Mbps"
echo "---------------------------------------------"