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limit precision for fragmentation in table

This commit is contained in:
Daniel Micay 2019-06-12 13:28:03 -04:00
parent 12525f2861
commit 37474e117c
2 changed files with 46 additions and 46 deletions
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90
README.md
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@ -367,41 +367,41 @@ preliminary set of values.
| size class | worst case internal fragmentation | slab slots | slab size | internal fragmentation for slabs |
| - | - | - | - | - |
| 16 | 93.75% | 256 | 4096 | 0.0% |
| 32 | 46.875% | 128 | 4096 | 0.0% |
| 32 | 46.88% | 128 | 4096 | 0.0% |
| 48 | 31.25% | 85 | 4096 | 0.390625% |
| 64 | 23.4375% | 64 | 4096 | 0.0% |
| 64 | 23.44% | 64 | 4096 | 0.0% |
| 80 | 18.75% | 51 | 4096 | 0.390625% |
| 96 | 15.625% | 42 | 4096 | 1.5625% |
| 112 | 13.392857142857139% | 36 | 4096 | 1.5625% |
| 128 | 11.71875% | 64 | 8192 | 0.0% |
| 160 | 19.375% | 51 | 8192 | 0.390625% |
| 192 | 16.145833333333343% | 64 | 12288 | 0.0% |
| 224 | 13.839285714285708% | 54 | 12288 | 1.5625% |
| 256 | 12.109375% | 64 | 16384 | 0.0% |
| 320 | 19.6875% | 64 | 20480 | 0.0% |
| 384 | 16.40625% | 64 | 24576 | 0.0% |
| 448 | 14.0625% | 64 | 28672 | 0.0% |
| 512 | 12.3046875% | 64 | 32768 | 0.0% |
| 640 | 19.84375% | 64 | 40960 | 0.0% |
| 768 | 16.536458333333343% | 64 | 49152 | 0.0% |
| 896 | 14.174107142857139% | 64 | 57344 | 0.0% |
| 1024 | 12.40234375% | 64 | 65536 | 0.0% |
| 1280 | 19.921875% | 16 | 20480 | 0.0% |
| 1536 | 16.6015625% | 16 | 24576 | 0.0% |
| 1792 | 14.229910714285708% | 16 | 28672 | 0.0% |
| 2048 | 12.451171875% | 16 | 32768 | 0.0% |
| 2560 | 19.9609375% | 8 | 20480 | 0.0% |
| 3072 | 16.634114583333343% | 8 | 24576 | 0.0% |
| 3584 | 14.2578125% | 8 | 28672 | 0.0% |
| 4096 | 12.4755859375% | 8 | 32768 | 0.0% |
| 5120 | 19.98046875% | 8 | 40960 | 0.0% |
| 6144 | 16.650390625% | 8 | 49152 | 0.0% |
| 7168 | 14.271763392857139% | 8 | 57344 | 0.0% |
| 8192 | 12.48779296875% | 8 | 65536 | 0.0% |
| 10240 | 19.990234375% | 6 | 61440 | 0.0% |
| 12288 | 16.658528645833343% | 5 | 61440 | 0.0% |
| 14336 | 14.278738839285708% | 4 | 57344 | 0.0% |
| 16384 | 12.493896484375% | 4 | 65536 | 0.0% |
| 96 | 15.62% | 42 | 4096 | 1.5625% |
| 112 | 13.39% | 36 | 4096 | 1.5625% |
| 128 | 11.72% | 64 | 8192 | 0.0% |
| 160 | 19.38% | 51 | 8192 | 0.390625% |
| 192 | 16.15% | 64 | 12288 | 0.0% |
| 224 | 13.84% | 54 | 12288 | 1.5625% |
| 256 | 12.11% | 64 | 16384 | 0.0% |
| 320 | 19.69% | 64 | 20480 | 0.0% |
| 384 | 16.41% | 64 | 24576 | 0.0% |
| 448 | 14.06% | 64 | 28672 | 0.0% |
| 512 | 12.3% | 64 | 32768 | 0.0% |
| 640 | 19.84% | 64 | 40960 | 0.0% |
| 768 | 16.54% | 64 | 49152 | 0.0% |
| 896 | 14.17% | 64 | 57344 | 0.0% |
| 1024 | 12.4% | 64 | 65536 | 0.0% |
| 1280 | 19.92% | 16 | 20480 | 0.0% |
| 1536 | 16.6% | 16 | 24576 | 0.0% |
| 1792 | 14.23% | 16 | 28672 | 0.0% |
| 2048 | 12.45% | 16 | 32768 | 0.0% |
| 2560 | 19.96% | 8 | 20480 | 0.0% |
| 3072 | 16.63% | 8 | 24576 | 0.0% |
| 3584 | 14.26% | 8 | 28672 | 0.0% |
| 4096 | 12.48% | 8 | 32768 | 0.0% |
| 5120 | 19.98% | 8 | 40960 | 0.0% |
| 6144 | 16.65% | 8 | 49152 | 0.0% |
| 7168 | 14.27% | 8 | 57344 | 0.0% |
| 8192 | 12.49% | 8 | 65536 | 0.0% |
| 10240 | 19.99% | 6 | 61440 | 0.0% |
| 12288 | 16.66% | 5 | 61440 | 0.0% |
| 14336 | 14.28% | 4 | 57344 | 0.0% |
| 16384 | 12.49% | 4 | 65536 | 0.0% |
The slab allocation size classes end at 16384 since that's the final size for
2048 byte spacing and the next spacing class matches the page size of 4096
@ -423,18 +423,18 @@ retaining the isolation.
| size class | worst case internal fragmentation | slab slots | slab size | internal fragmentation for slabs |
| - | - | - | - | - |
| 20480 | 19.9951171875% | 2 | 40960 | 0.0% |
| 24576 | 16.66259765625% | 2 | 49152 | 0.0% |
| 28672 | 14.2822265625% | 2 | 57344 | 0.0% |
| 32768 | 12.4969482421875% | 2 | 65536 | 0.0% |
| 40960 | 19.99755859375% | 1 | 40960 | 0.0% |
| 49152 | 16.664632161458343% | 1 | 49152 | 0.0% |
| 57344 | 14.283970424107139% | 1 | 57344 | 0.0% |
| 65536 | 12.49847412109375% | 1 | 65536 | 0.0% |
| 81920 | 19.998779296875% | 1 | 81920 | 0.0% |
| 98304 | 16.6656494140625% | 1 | 98304 | 0.0% |
| 114688 | 14.284842354910708% | 1 | 114688 | 0.0% |
| 131072 | 12.499237060546875% | 1 | 131072 | 0.0% |
| 20480 | 20.0% | 2 | 40960 | 0.0% |
| 24576 | 16.66% | 2 | 49152 | 0.0% |
| 28672 | 14.28% | 2 | 57344 | 0.0% |
| 32768 | 12.5% | 2 | 65536 | 0.0% |
| 40960 | 20.0% | 1 | 40960 | 0.0% |
| 49152 | 16.66% | 1 | 49152 | 0.0% |
| 57344 | 14.28% | 1 | 57344 | 0.0% |
| 65536 | 12.5% | 1 | 65536 | 0.0% |
| 81920 | 20.0% | 1 | 81920 | 0.0% |
| 98304 | 16.67% | 1 | 98304 | 0.0% |
| 114688 | 14.28% | 1 | 114688 | 0.0% |
| 131072 | 12.5% | 1 | 131072 | 0.0% |
The `CONFIG_LARGE_SIZE_CLASSES` option controls whether large allocations use
the same size class scheme providing 4 size classes for every doubling of size.

2
calculate_waste.py
View File

@ -49,7 +49,7 @@ for size, slots, fragmentation in zip(size_classes, size_class_slots, fragmentat
used = size * slots
real = page_align(used)
print("| ", end='')
print(size, str(fragmentation) + "%", slots, real, str(100 - used / real * 100) + "%", sep=" | ", end=" |\n")
print(size, f"{fragmentation:.4}%", slots, real, str(100 - used / real * 100) + "%", sep=" | ", end=" |\n")
if len(argv) < 2:
exit()