Compress in-memory representation of FunctionAddressMap
#2321
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This commit compresses `FunctionAddressMap` by performing a simple coalescing of adjacent `InstructionAddressMap` descriptors if they describe the same source location. This is intended to handle the common case where a sequene of machine instructions describes a high-level wasm instruction. For the module on bytecodealliance#2318 this reduces the cache entry size from 306MB to 161MB.
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yurydelendik
approved these changes
Oct 26, 2020
alexcrichton
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Oct 26, 2020
This commit reduces the size of `InstructionAddressMap` from 24 bytes to 8 bytes by dropping the `code_len` field and reducing `code_offset` to `u32` instead of `usize`. The intention is to primarily make the in-memory version take up less space, and the hunch is that the `code_len` is largely not necessary since most entries in this map are always adjacent to one another. The `code_len` field is now implied by the `code_offset` field of the next entry in the map. This isn't as big of an improvement to serialized module size as bytecodealliance#2321 or bytecodealliance#2322, primarily because of the switch to variable-length encoding. Despite this though it shaves about 10MB off the encoded size of the module from bytecodealliance#2318
alexcrichton
added a commit
to alexcrichton/wasmtime
that referenced
this pull request
Oct 27, 2020
This commit reduces the size of `InstructionAddressMap` from 24 bytes to 8 bytes by dropping the `code_len` field and reducing `code_offset` to `u32` instead of `usize`. The intention is to primarily make the in-memory version take up less space, and the hunch is that the `code_len` is largely not necessary since most entries in this map are always adjacent to one another. The `code_len` field is now implied by the `code_offset` field of the next entry in the map. This isn't as big of an improvement to serialized module size as bytecodealliance#2321 or bytecodealliance#2322, primarily because of the switch to variable-length encoding. Despite this though it shaves about 10MB off the encoded size of the module from bytecodealliance#2318
alexcrichton
added a commit
to alexcrichton/wasmtime
that referenced
this pull request
Nov 3, 2020
This commit reduces the size of `InstructionAddressMap` from 24 bytes to 8 bytes by dropping the `code_len` field and reducing `code_offset` to `u32` instead of `usize`. The intention is to primarily make the in-memory version take up less space, and the hunch is that the `code_len` is largely not necessary since most entries in this map are always adjacent to one another. The `code_len` field is now implied by the `code_offset` field of the next entry in the map. This isn't as big of an improvement to serialized module size as bytecodealliance#2321 or bytecodealliance#2322, primarily because of the switch to variable-length encoding. Despite this though it shaves about 10MB off the encoded size of the module from bytecodealliance#2318
alexcrichton
added a commit
that referenced
this pull request
Nov 3, 2020
This commit reduces the size of `InstructionAddressMap` from 24 bytes to 8 bytes by dropping the `code_len` field and reducing `code_offset` to `u32` instead of `usize`. The intention is to primarily make the in-memory version take up less space, and the hunch is that the `code_len` is largely not necessary since most entries in this map are always adjacent to one another. The `code_len` field is now implied by the `code_offset` field of the next entry in the map. This isn't as big of an improvement to serialized module size as #2321 or #2322, primarily because of the switch to variable-length encoding. Despite this though it shaves about 10MB off the encoded size of the module from #2318
cfallin
pushed a commit
that referenced
this pull request
Nov 30, 2020
This commit compresses `FunctionAddressMap` by performing a simple coalescing of adjacent `InstructionAddressMap` descriptors if they describe the same source location. This is intended to handle the common case where a sequene of machine instructions describes a high-level wasm instruction. For the module on #2318 this reduces the cache entry size from 306MB to 161MB.
cfallin
pushed a commit
that referenced
this pull request
Nov 30, 2020
This commit reduces the size of `InstructionAddressMap` from 24 bytes to 8 bytes by dropping the `code_len` field and reducing `code_offset` to `u32` instead of `usize`. The intention is to primarily make the in-memory version take up less space, and the hunch is that the `code_len` is largely not necessary since most entries in this map are always adjacent to one another. The `code_len` field is now implied by the `code_offset` field of the next entry in the map. This isn't as big of an improvement to serialized module size as #2321 or #2322, primarily because of the switch to variable-length encoding. Despite this though it shaves about 10MB off the encoded size of the module from #2318
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This commit compresses
FunctionAddressMapby performing a simplecoalescing of adjacent
InstructionAddressMapdescriptors if theydescribe the same source location. This is intended to handle the common
case where a sequene of machine instructions describes a high-level wasm
instruction.
For the module on #2318 this reduces the cache entry size from 306MB to
161MB.