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| − | Session 1, x86 optimization: | + | '''Session 1, x86 optimization''': |
C/C++: increase the execution speed for the code that reverses the order of the bits composing a 100 M esantioane of unsigned 32-bit (eg. 10111...11 -> 11..11101) | C/C++: increase the execution speed for the code that reverses the order of the bits composing a 100 M esantioane of unsigned 32-bit (eg. 10111...11 -> 11..11101) | ||
| Linia 5: | Linia 5: | ||
Expected/Presented techniques: | Expected/Presented techniques: | ||
| − | first implementation ~ 10 seconds | + | Grade 7/10: first implementation ~ 10 seconds |
| − | compiler optimized ~ 5 seconds | + | Grade 8/10: compiler optimized ~ 5 seconds |
| − | loop unrolling | + | Grade 9/10: |
| + | loop unrolling ( > 1s ) | ||
| − | + | optimizing variables into registers ( > 1s ) | |
| − | + | Grade 10: bit-tricks 500 ms | |
| − | 256-entry 8-bit table of 1 KB | + | Grade 10: 256-entry 8-bit table of 1 KB ~ 400 ms |
| − | 16-bit table of 64 k entries (256 KB) | + | Grade 10: 16-bit table of 64 k entries (256 KB) ~ 200 ms |
| − | 32-bit table of 4 G entries (16 GB) | + | 32-bit table of 4 G entries (16 GB) ~ 66 ms |
Versiunea curentă din 8 martie 2018 13:53
Session 1, x86 optimization:
C/C++: increase the execution speed for the code that reverses the order of the bits composing a 100 M esantioane of unsigned 32-bit (eg. 10111...11 -> 11..11101)
Expected/Presented techniques:
Grade 7/10: first implementation ~ 10 seconds
Grade 8/10: compiler optimized ~ 5 seconds
Grade 9/10: loop unrolling ( > 1s )
optimizing variables into registers ( > 1s )
Grade 10: bit-tricks 500 ms
Grade 10: 256-entry 8-bit table of 1 KB ~ 400 ms
Grade 10: 16-bit table of 64 k entries (256 KB) ~ 200 ms
32-bit table of 4 G entries (16 GB) ~ 66 ms
