xref: /aosp_15_r20/external/zstd/contrib/largeNbDicts/README.md (revision 01826a4963a0d8a59bc3812d29bdf0fb76416722)
1*01826a49SYabin CuilargeNbDicts
2*01826a49SYabin Cui=====================
3*01826a49SYabin Cui
4*01826a49SYabin Cui`largeNbDicts` is a benchmark test tool
5*01826a49SYabin Cuidedicated to the specific scenario of
6*01826a49SYabin Cuidictionary decompression using a very large number of dictionaries.
7*01826a49SYabin CuiWhen dictionaries are constantly changing, they are always "cold",
8*01826a49SYabin Cuisuffering from increased latency due to cache misses.
9*01826a49SYabin Cui
10*01826a49SYabin CuiThe tool is created in a bid to investigate performance for this scenario,
11*01826a49SYabin Cuiand experiment mitigation techniques.
12*01826a49SYabin Cui
13*01826a49SYabin CuiCommand line :
14*01826a49SYabin Cui```
15*01826a49SYabin CuilargeNbDicts [Options] filename(s)
16*01826a49SYabin Cui
17*01826a49SYabin CuiOptions :
18*01826a49SYabin Cui-z          : benchmark compression (default)
19*01826a49SYabin Cui-d          : benchmark decompression
20*01826a49SYabin Cui-r          : recursively load all files in subdirectories (default: off)
21*01826a49SYabin Cui-B#         : split input into blocks of size # (default: no split)
22*01826a49SYabin Cui-#          : use compression level # (default: 3)
23*01826a49SYabin Cui-D #        : use # as a dictionary (default: create one)
24*01826a49SYabin Cui-i#         : nb benchmark rounds (default: 6)
25*01826a49SYabin Cui--nbBlocks=#: use # blocks for bench (default: one per file)
26*01826a49SYabin Cui--nbDicts=# : create # dictionaries for bench (default: one per block)
27*01826a49SYabin Cui-h          : help (this text)
28*01826a49SYabin Cui
29*01826a49SYabin CuiAdvanced Options (see zstd.h for documentation) :
30*01826a49SYabin Cui--dedicated-dict-search
31*01826a49SYabin Cui--dict-content-type=#
32*01826a49SYabin Cui--dict-attach-pref=#
33*01826a49SYabin Cui```
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