nushell/crates/nu-engine/src
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
..
call_ext.rs Document and critically review ShellError variants - Ep. 3 (#8340) 2023-03-06 18:33:09 +01:00
column.rs Add values command (see #7166) (#7583) 2022-12-23 12:49:19 -06:00
documentation.rs FEATURE: print example command results in the help (#8189) 2023-02-26 21:05:11 +01:00
env.rs Document and critically review ShellError variants - Ep. 3 (#8340) 2023-03-06 18:33:09 +01:00
eval.rs Box ShellError in Value::Error (#8375) 2023-03-12 09:57:27 +01:00
glob_from.rs Run a round of clippy --fix to fix a ton of lints (#7006) 2022-11-04 15:11:17 -05:00
lib.rs LazyRecord (#7619) 2023-01-18 19:27:26 -08:00
nu_variable.rs FEATURE: add the startup time to $nu (#8353) 2023-03-09 14:18:58 -06:00
scope.rs Reworking help aliases (#8372) 2023-03-10 20:14:55 +02:00