Skip to main content

Loading the code workspace…

LC

Implement CPU Affinity: Pin Processes to Specific Cores

medium8/9

Implement Multi-Level Feedback Queue Scheduler Measure Scheduling Latency Using Clock Functions

Language

Compiler

2.0s Limit 256MB

Submit and pass all tests to enable saving to GitHub.

Implementation

Implement CPU affinity for process pinning.

Requirements:

Add cpu_affinity_mask field to Process structure (bitmask)
Implement sched_setaffinity(pid, mask) system call
Implement sched_getaffinity(pid) to retrieve mask
Modify scheduler to only select from allowed CPUs
Check that CPU number is valid (0 to num_cpus-1)
Maintain per-CPU run queues
Demonstrate process pinned to single CPU
Demonstrate process pinned to multiple CPUs
Show load imbalance when processes are pinned
Handle error cases: invalid CPU, process doesn't exist

Test scenarios:

Pin process to CPU 0 (mask = 0x1)
Pin process to CPUs 0 and 1 (mask = 0x3)
Pin process to all CPUs (mask = 0xFF, default)
Try to pin to invalid CPU (error)
Show scheduler respecting affinity

Why This Matters

This is the exact mechanism behind Linux's `taskset` and `sched_setaffinity(2)`, which production systems use to pin latency-sensitive workloads like Redis or DPDK packet processors away from cores handling interrupts, avoiding cache-line bouncing across NUMA nodes. Getting affinity-aware load balancing wrong is a real operational trap: pinning too many processes to one core creates the exact imbalance this task asks you to demonstrate.

Hints

0 / 3 revealed

Validation Suite

main.c

Workspace 1.0

← Implement Multi-Level Feedback Queue SchedulerMeasure Scheduling Latency Using Clock Functions →