nushell/crates/nu-command
Stefan Holderbach a52386e837
Box ShellError in Value::Error (#8375)
# Description

Our `ShellError` at the moment has a `std::mem::size_of<ShellError>` of
136 bytes (on AMD64). As a result `Value` directly storing the struct
also required 136 bytes (thanks to alignment requirements).

This change stores the `Value::Error` `ShellError` on the heap.

Pro:
- Value now needs just 80 bytes
- Should be 1 cacheline less (still at least 2 cachelines)

Con:
- More small heap allocations when dealing with `Value::Error`
  - More heap fragmentation
  - Potential for additional required memcopies

# Further code changes

Includes a small refactor of `try` due to a type mismatch in its large
match.

# User-Facing Changes

None for regular users.

Plugin authors may have to update their matches on `Value` if they use
`nu-protocol`

Needs benchmarking to see if there is a benefit in real world workloads.
**Update** small improvements in runtime for workloads with high volume
of values. Significant reduction in maximum resident set size, when many
values are held in memory.

# Tests + Formatting
2023-03-12 09:57:27 +01:00
..
assets refactor html module (#5246) 2022-04-20 08:50:14 -05:00
proptest-regressions/format_conversions add tests, deal with pipes, newlines, tabs for to nuon (#6391) 2022-09-01 14:08:19 +02:00
src Box ShellError in Value::Error (#8375) 2023-03-12 09:57:27 +01:00
tests New xml format (#7947) 2023-03-12 12:35:42 +13:00
Cargo.toml Revert to notify v4 (#8367) 2023-03-08 21:45:58 -08:00
LICENSE Include license text in all crates (#5094) 2022-04-08 10:47:13 +02:00