Amdahl's Law Calculator

Calculate theoretical speedup in parallel computing and task optimization

Calculate Amdahl's Law Speedup

%

Percentage of task that can be parallelized

How much faster the parallel part becomes

Time before any improvements

Sequential Part Optimization

How much faster the sequential part becomes

Speedup Analysis

1.00x
Current Speedup
1.00x
Max Speedup
1.00x
With Optimization
0.0%
Improvement

Amdahl's Law Formula

S = 1 / ((1 - p) + p/s)
Where: S = Speedup, p = Parallel proportion, s = Speedup factor

Example Calculation

Video Processing Task

Original time: 120 seconds

Parallelizable: 40% of task

Speedup factor: 4x (using 4 cores)

Result

Speedup: S = 1 / (0.6 + 0.4/4) = 1.43x

New time: 120 / 1.43 = 83.9 seconds

30% improvement

Key Insights

💡

Sequential parts limit overall speedup

💡

Infinite resources can't overcome serial bottlenecks

💡

Focus on parallelizing large portions of work

💡

Optimize sequential parts for better gains

Applications

Parallel Computing
Multi-core processor optimization
Algorithm Design
Identifying parallelizable sections
Performance Analysis
Resource allocation decisions
System Design
Distributed system optimization

Understanding Amdahl's Law

What is Amdahl's Law?

Amdahl's Law predicts the theoretical speedup when a portion of a task is improved. It shows that the speedup is limited by the sequential (non-parallelizable) portion of the task, highlighting the importance of optimizing the right parts.

Key Implications

  • •Sequential parts create performance bottlenecks
  • •Adding more processors has diminishing returns
  • •Focus on parallelizing large task portions
  • •Sequential optimization can be more effective

Formula Breakdown

Basic Formula

S = 1 / ((1-p) + p/s)

S: Theoretical speedup

p: Proportion parallelized (0-1)

s: Speedup factor of parallel part

Maximum Speedup

S_max = 1 / (1-p)
Theoretical limit with infinite resources

Limitations of Amdahl's Law

Assumptions

  • • Fixed workload size
  • • Perfect parallelization
  • • No communication overhead
  • • Homogeneous processors

Real-World Factors

  • • Memory bandwidth limits
  • • Cache coherency overhead
  • • Load balancing issues
  • • Synchronization costs