LABORATORY 05 · COMPUTER SCIENCE

Empirical Analysis of the Queue Abstract Data Type: Circular Ring Buffers, Modular Indexing, and Producer-Consumer Data Flow

Determine the unit packet throughput volume L_packet from empirical ring buffer memory bus transfer across batch stream sizes. Explore interactive search algorithms, compare operation counts and analyse complexity scaling.

COMPUTE · BENCHMARK · ANALYSE

Your virtual algorithm laboratory.

CUMULATIVE BUFFER MEMORY TRANSFER VOLUME V—

EXECUTION STATUS

Ready to execute batch size benchmark.

Processed packet batch size n (packets)1024 packetsSet batch size (packets)

Circular ring buffer allocated in contiguous physical memory with 12-slot capacity and zero runtime heap reallocations.

Adjust batch size n, then execute benchmark.

Operation counts are generated deterministically by the exact algorithmic execution model. Modern hardware benchmarks additionally reflect cache line prefetching and branch misprediction penalties.

Algorithmic assumptions and limits

The simulated execution model evaluates idealized streaming throughput through a 12-slot circular ring buffer with fixed 64-byte packet payloads and a 256-byte cache-padded descriptor header. In physical microprocessors, actual memory bus throughput is modulated by DRAM bus width, memory controller scheduling, prefetcher stride detectors, NUMA (Non-Uniform Memory Access) node latency when producers and consumers reside on separate CPU sockets, and operating system scheduler interrupt latencies during thread synchronization. The simulated benchmark environment reflects standard high-performance systems architecture, where each streaming network packet payload occupies exactly one standard CPU cache line (64 bytes). The circular ring buffer control block occupies 256 bytes of metadata overhead (including 64-byte padded atomic head and tail pointers to prevent false sharing). Consequently, transmitting a batch of n packets through the circular ring buffer yields an exact linear memory bus transfer volume V(n) = 64.0000 · n + 256.0000 bytes, providing an ideal microarchitectural model for Ordinary Least-Squares regression.

Computational tools & environment.

Circular Ring Buffer Array

Fixed-size contiguous memory block of N slots managed via modular indexing pointers, executing O(1) FIFO operations without memory reallocation.

Modular Index Calculator

Microarchitectural arithmetic logic unit computing cyclic pointer advances: next = (current + 1) mod N and occupancy = (rear - front + N) mod N.

Cache-Padded Descriptor Block

256-byte ring buffer control header with atomic head and tail pointers segregated onto independent 64-byte cache lines to eliminate false sharing.

Producer Task Simulator

Asynchronous streaming payload generator writing 64-byte data packets into available buffer slots and advancing the atomic rear cursor.

Consumer Task Simulator

Asynchronous message processor draining 64-byte data packets from the front cursor and updating buffer occupancy state.

Memory Bus Telemetry Monitor

High-precision hardware register tracking cumulative byte throughput, cache line writebacks, and full buffer overflow events.

FOLLOW THE METHOD

A reason behind every step.

Determine the unit packet throughput volume L_packet from empirical ring buffer memory bus transfer across batch stream sizes. Suggested independent settings: 256, 512, 1024, 2048, 4096, 8192, 16384 packets.

Initialize Circular Buffer & Telemetry Registers

Configure the virtual memory environment with a 12-slot circular ring buffer, verify 64-byte cache line alignment, and confirm the base descriptor overhead V_0 = 256 bytes.

Select Packet Batch Size

Adjust the independent variable control slider to choose a transmission batch size n between 256 and 16,384 packets across the designated benchmark sample points.

Execute Stream Transmission Benchmark

Trigger the streaming pipeline, executing continuous producer enqueue and consumer dequeue cycles that advance the modular front and rear cursors around the circular array.

Measure Cumulative Memory Bus Throughput

Upon completion of the batch transfer, capture the total memory volume V = 64n + 256 bytes from the memory bus telemetry profiler.

Record Benchmark Observation in Notebook

Log the independent batch count n (packets) and dependent transfer volume V (bytes) into the laboratory notebook table and plot the corresponding data coordinate.

Perform Regression & Architectural Analysis

Calculate the ordinary least-squares regression line V = L_packet · n + V_0 across all seven benchmark trials to extract the unit packet payload size L_packet and verify agreement with the 64-byte cache line standard.

YOUR NOTEBOOK · 0 OBSERVATIONS

Turn measurements into asymptotic insight.

See a complete example report ↗

Points are your recorded benchmark observations. The regression line validates Queue ADT & Ring Buffer Architecture complexity scaling.

LINEAR ASYMPTOTIC FIT · y = mx + b

V(n) = L_packet · n + V_0 = 64.0000 · n + 256.0000 bytes

#	Processed packet batch size n (packets) (packets)	Cumulative buffer memory transfer volume V (bytes)	Batch packet count n (packets)	Memory bus transfer volume V (bytes)	Remove

No readings yet. Execute a batch size benchmark and record it.

Calculate it yourself.

Your estimate of L_packet (bytes/packet)

CHECK YOUR UNDERSTANDING

Explain what the operation counts mean.

Why does a naive array implementation of a queue suffer from either O(n) operational complexity or memory pointer drift?

When the capacity N of a circular ring buffer is an exact power of two (N = 2^k), how can the modular indexing operation (index mod N) be microarchitecturally optimized?

What is the phenomenon of False Sharing in multi-core concurrent circular ring buffers, and how is it resolved?

In the Producer-Consumer problem with a bounded circular buffer, what theorem from Queuing Theory dictates that the average number of items in the system L equals the arrival rate λ multiplied by average waiting time W?