## Bar Charts: Speedup Comparison of Sorting Algorithms on Different GPUs
### Overview
The image contains six bar charts comparing the speedup of three sorting algorithms (WMS, BMS, RB-Sort) across different numbers of buckets (m) on two GPUs (Tesla K40c and GeForce GTX 1080). The charts are divided into two scenarios: "key-only" and "key-value", with two GPU configurations each (ECC on/off).
### Components/Axes
- **X-axis**: "Number of buckets (m)" with values: 2, 4, 8, 16, 32, 64, 128, 256.
- **Y-axis**: "Speedup" with a scale from 0 to 10.
- **Legends**: Located in the top-right of each chart, with colors:
- Yellow: WMS
- Green: BMS
- Blue: RB-Sort
- **Chart Titles**:
- (a) Key-only: Tesla K40c (ECC on)
- (b) Key-only: Tesla K40c (ECC off)
- (c) Key-only: GeForce GTX 1080
- (d) Key-value: Tesla K40c (ECC on)
- (e) Key-value: Tesla K40c (ECC off)
- (f) Key-value: GeForce GTX 1080
### Detailed Analysis
#### Key-only: Tesla K40c (ECC on)
- **WMS**: Speedup decreases from ~9.5 (m=2) to ~2.5 (m=256).
- **BMS**: Speedup decreases from ~6.5 (m=2) to ~2.0 (m=256).
- **RB-Sort**: Speedup decreases from ~4.0 (m=2) to ~1.5 (m=256).
#### Key-only: Tesla K40c (ECC off)
- **WMS**: Speedup decreases from ~8.0 (m=2) to ~2.0 (m=256).
- **BMS**: Speedup decreases from ~5.0 (m=2) to ~1.8 (m=256).
- **RB-Sort**: Speedup decreases from ~3.5 (m=2) to ~1.2 (m=256).
#### Key-only: GeForce GTX 1080
- **WMS**: Speedup decreases from ~6.0 (m=2) to ~2.5 (m=256).
- **BMS**: Speedup decreases from ~5.5 (m=2) to ~2.0 (m=256).
- **RB-Sort**: Speedup decreases from ~3.0 (m=2) to ~1.5 (m=256).
#### Key-value: Tesla K40c (ECC on)
- **WMS**: Speedup decreases from ~10.0 (m=2) to ~3.0 (m=256).
- **BMS**: Speedup decreases from ~8.0 (m=2) to ~2.5 (m=256).
- **RB-Sort**: Speedup decreases from ~3.5 (m=2) to ~1.5 (m=256).
#### Key-value: Tesla K40c (ECC off)
- **WMS**: Speedup decreases from ~8.5 (m=2) to ~2.0 (m=256).
- **BMS**: Speedup decreases from ~6.0 (m=2) to ~1.8 (m=256).
- **RB-Sort**: Speedup decreases from ~3.0 (m=2) to ~1.2 (m=256).
#### Key-value: GeForce GTX 1080
- **WMS**: Speedup decreases from ~6.0 (m=2) to ~2.5 (m=256).
- **BMS**: Speedup decreases from ~5.5 (m=2) to ~2.0 (m=256).
- **RB-Sort**: Speedup decreases from ~3.0 (m=2) to ~1.5 (m=256).
### Key Observations
1. **WMS consistently outperforms BMS and RB-Sort** across all configurations, with the highest speedup at m=2.
2. **Speedup decreases as the number of buckets (m) increases**, with the steepest drop between m=2 and m=4.
3. **ECC off configurations show slightly lower speedups** compared to ECC on for the same GPU and scenario.
4. **Key-value scenarios generally have higher speedups** than key-only for the same GPU and ECC settings.
5. **RB-Sort underperforms BMS in most cases**, particularly at higher m values.
### Interpretation
The data suggests that **WMS is the most efficient algorithm** for sorting on both GPUs, especially for small bucket sizes (m=2). The performance degradation with increasing m indicates a trade-off between bucket count and speedup. ECC off configurations slightly reduce performance, but the difference is less pronounced in key-value scenarios. RB-Sort’s lower speedup highlights its inefficiency compared to WMS and BMS. The results emphasize the importance of algorithm selection based on hardware (GPU) and data characteristics (key-only vs key-value).
