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calculate internal slab fragmentation from slots

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Daniel Micay 2018-08-23 17:39:32 -04:00
parent 5bdf94da4a
commit 5a1a76f94e
1 changed files with 23 additions and 0 deletions
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23
calculate_waste.py
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@ -1,5 +1,7 @@
#!/usr/bin/env python3
from sys import argv
size_classes = [
16, 32, 48, 64, 80, 96, 112, 128,
160, 192, 224, 256,
@ -11,6 +13,17 @@ size_classes = [
10240, 12288, 14336, 16384
]
size_class_slots = [
256, 128, 128, 64, 51, 42, 36, 64,
51, 64, 64, 64,
64, 64, 64, 64,
64, 64, 64, 64,
16, 16, 16, 16,
8, 8, 8, 8,
8, 8, 8, 8,
5, 6, 4, 4
]
print("size class", "worst case internal fragmentation", sep=", ")
print(16, "100%", sep=", ")
@ -24,6 +37,16 @@ for i in range(len(size_classes) - 1):
def page_align(size):
return (size + 4095) & ~4095
print()
print("size class", "slab slots", "worst case internal fragmentation for slabs", sep=", ")
for size, slots in zip(size_classes, size_class_slots):
used = size * slots
real = page_align(used)
print(size, slots, str(100 - used / real * 100) + "%", sep=", ")
if len(argv) < 2:
exit()
max_bits = 256
max_page_span = 16