Reduce size of HTML Flame Graph #864
Description
Background
async-profiler dumps a Flame Graph as a JavaScript having one function call per frame:
f(165,557,1,1,'dotty/tools/dotc/core/Types$TypeMap.mapArgs')
f(166,557,1,1,'dotty/tools/dotc/core/Types$TypeMap.mapArgs')
f(167,557,1,1,'dotty/tools/dotc/core/Types$TypeMap.mapArgs')
f(168,557,1,1,'dotty/tools/dotc/core/Types$TypeMap.mapArgs')
f(56,558,7,1,'dotty/tools/backend/jvm/BCodeBodyBuilder$PlainBodyBuilder.genWhileDo')
f(57,558,7,1,'dotty/tools/backend/jvm/BCodeBodyBuilder$PlainBodyBuilder.genLoad')
f(58,558,7,1,'dotty/tools/backend/jvm/BCodeBodyBuilder$PlainBodyBuilder.genBlock')
f(59,558,7,1,'dotty/tools/backend/jvm/BCodeBodyBuilder$PlainBodyBuilder.genLoad')
f(60,558,7,1,'dotty/tools/backend/jvm/BCodeBodyBuilder$PlainBodyBuilder.genLoadIf')
f(61,559,6,1,'dotty/tools/backend/jvm/BCodeBodyBuilder$PlainBodyBuilder.genLoad')
f(62,559,6,1,'dotty/tools/backend/jvm/BCodeBodyBuilder$PlainBodyBuilder.genLoadIf')
f(63,559,6,1,'dotty/tools/backend/jvm/BCodeBodyBuilder$PlainBodyBuilder.genLoad')
Many frames have the same title which is repeated each time.
We can reduce the script size by deduplicating frame titles.
Proposal
Move strings representing frame titles to a separate array (constant pool), and refer this array by indices.
As an example, string deduplication reduces the flame graph size of the dotty benchmark by 2.5x.
Further compression of the string pool and frame descriptors leads to the total of 5.5x size reduction.
| Old Flame Graph | + String dedup | + Compression |
|---|---|---|
| 4182 KB | 1644 KB | 759 KB |