Sequential: One task at a time. Total time = sum of all task times. Simple but slow. Like one person washing all the dishes.
Parallel: Multiple tasks simultaneously on separate cores/processors. Total time ≈ longest single task. Like 4 people each washing ¼ of the dishes.
Speedup: Speedup = Sequential Time / Parallel Time. With 4 cores and perfectly parallelizable work, maximum speedup = 4×.
Amdahl's Law: Speedup is limited by the sequential portion of the program. If 25% of work is inherently sequential, maximum speedup is only 4× regardless of processor count.
Tags
ParallelSequentialSpeedupAmdahl's Law
Configuration
Processor Cores = 1
Total Tasks = 8
Sequential % = 0%
PERFORMANCE COMPARISON
Sequential time:8.0s
Parallel time:8.0s
Speedup:1.0×
Efficiency:100%
Start with 1 core: Everything is sequential. Increase cores to see tasks distributed across processors. Notice that speedup is limited by the sequential portion (Amdahl's Law) — adding more cores has diminishing returns.