Add --long flag for sys cpu (#14485)

# Description

Fixes #14470 where the `sys cpu` command is slow. This was done by
removing the `cpu_usage` column from the default output, since it takes
400ms to calculate. Instead a `--long` flag was added that, when
provided, adds back the `cpu_usage` column.

```nu
# Before
> bench { sys cpu | length } | get mean
401ms 591µs 896ns

# After
> bench { sys cpu | length } | get mean
500µs 13ns # around 1-2ms in practice
```

# User-Facing Changes

- `sys cpu` no longer has a `cpu_usage` column by default.
- Added  a `--long` flag for `sys cpu` to add back the removed column.
This commit is contained in:
Ian Manske 2024-12-01 03:56:42 -08:00 committed by GitHub
parent 88d27fd607
commit c560bac13f
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
2 changed files with 32 additions and 20 deletions

View File

@ -13,6 +13,11 @@ impl Command for SysCpu {
fn signature(&self) -> Signature {
Signature::build("sys cpu")
.filter()
.switch(
"long",
"Get all available columns (slower, needs to sample CPU over time)",
Some('l'),
)
.category(Category::System)
.input_output_types(vec![(Type::Nothing, Type::table())])
}
@ -23,12 +28,13 @@ impl Command for SysCpu {
fn run(
&self,
_engine_state: &EngineState,
_stack: &mut Stack,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
_input: PipelineData,
) -> Result<PipelineData, ShellError> {
Ok(cpu(call.head).into_pipeline_data())
let long = call.has_flag(engine_state, stack, "long")?;
Ok(cpu(long, call.head).into_pipeline_data())
}
fn examples(&self) -> Vec<Example> {
@ -40,38 +46,44 @@ impl Command for SysCpu {
}
}
fn cpu(span: Span) -> Value {
fn cpu(long: bool, span: Span) -> Value {
let mut sys = System::new();
sys.refresh_cpu_specifics(CpuRefreshKind::everything());
// We must refresh the CPU twice a while apart to get valid usage data.
// In theory we could just sleep MINIMUM_CPU_UPDATE_INTERVAL, but I've noticed that
// that gives poor results (error of ~5%). Decided to wait 2x that long, somewhat arbitrarily
std::thread::sleep(MINIMUM_CPU_UPDATE_INTERVAL * 2);
sys.refresh_cpu_specifics(CpuRefreshKind::new().with_cpu_usage());
if long {
sys.refresh_cpu_specifics(CpuRefreshKind::everything());
// We must refresh the CPU twice a while apart to get valid usage data.
// In theory we could just sleep MINIMUM_CPU_UPDATE_INTERVAL, but I've noticed that
// that gives poor results (error of ~5%). Decided to wait 2x that long, somewhat arbitrarily
std::thread::sleep(MINIMUM_CPU_UPDATE_INTERVAL * 2);
sys.refresh_cpu_specifics(CpuRefreshKind::new().with_cpu_usage());
} else {
sys.refresh_cpu_specifics(CpuRefreshKind::new().with_frequency());
}
let cpus = sys
.cpus()
.iter()
.map(|cpu| {
// sysinfo CPU usage numbers are not very precise unless you wait a long time between refreshes.
// Round to 1DP (chosen somewhat arbitrarily) so people aren't misled by high-precision floats.
let rounded_usage = (cpu.cpu_usage() * 10.0).round() / 10.0;
let load_avg = System::load_average();
let load_avg = format!(
"{:.2}, {:.2}, {:.2}",
load_avg.one, load_avg.five, load_avg.fifteen
);
let record = record! {
let mut record = record! {
"name" => Value::string(trim_cstyle_null(cpu.name()), span),
"brand" => Value::string(trim_cstyle_null(cpu.brand()), span),
"freq" => Value::int(cpu.frequency() as i64, span),
"cpu_usage" => Value::float(rounded_usage.into(), span),
"load_average" => Value::string(load_avg, span),
"vendor_id" => Value::string(trim_cstyle_null(cpu.vendor_id()), span),
"freq" => Value::int(cpu.frequency() as i64, span),
"load_average" => Value::string(load_avg, span),
};
if long {
// sysinfo CPU usage numbers are not very precise unless you wait a long time between refreshes.
// Round to 1DP (chosen somewhat arbitrarily) so people aren't misled by high-precision floats.
let rounded_usage = (f64::from(cpu.cpu_usage()) * 10.0).round() / 10.0;
record.push("cpu_usage", rounded_usage.into_value(span));
}
Value::record(record, span)
})
.collect();

View File

@ -3,6 +3,6 @@ pub use nu_protocol::{
ast::CellPath,
engine::{Call, Command, EngineState, Stack, StateWorkingSet},
record, ByteStream, ByteStreamType, Category, ErrSpan, Example, IntoInterruptiblePipelineData,
IntoPipelineData, IntoSpanned, PipelineData, Record, ShellError, Signature, Span, Spanned,
SyntaxShape, Type, Value,
IntoPipelineData, IntoSpanned, IntoValue, PipelineData, Record, ShellError, Signature, Span,
Spanned, SyntaxShape, Type, Value,
};