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Box ShellError in Value::Error (#8375)

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# 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
This commit is contained in:
Stefan Holderbach
2023-03-12 09:57:27 +01:00
committed by GitHub
parent c26d91fb61
commit a52386e837
153 changed files with 648 additions and 520 deletions
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16
crates/nu-command/src/dataframe/values/nu_dataframe/conversion.rs
View File

@ -461,13 +461,13 @@ pub fn create_column(
Some(val) => val,
None => {
return Value::Error {
error: ShellError::UnsupportedInput(
error: Box::new(ShellError::UnsupportedInput(
"The given local datetime representation is invalid."
.to_string(),
format!("timestamp is {a:?}"),
span,
Span::unknown(),
),
)),
}
}
};
@ -476,13 +476,13 @@ pub fn create_column(
Some(val) => val,
None => {
return Value::Error {
error: ShellError::UnsupportedInput(
error: Box::new(ShellError::UnsupportedInput(
"The given local datetime representation is invalid."
.to_string(),
format!("timestamp is {a:?}"),
span,
Span::unknown(),
),
)),
}
}
};
@ -526,13 +526,13 @@ pub fn create_column(
Some(val) => val,
None => {
return Value::Error {
error: ShellError::UnsupportedInput(
error: Box::new(ShellError::UnsupportedInput(
"The given local datetime representation is invalid."
.to_string(),
format!("timestamp is {a:?}"),
span,
Span::unknown(),
),
)),
}
}
};
@ -541,13 +541,13 @@ pub fn create_column(
Some(val) => val,
None => {
return Value::Error {
error: ShellError::UnsupportedInput(
error: Box::new(ShellError::UnsupportedInput(
"The given local datetime representation is invalid."
.to_string(),
format!("timestamp is {a:?}"),
span,
Span::unknown(),
),
)),
}
}
};