Revision control
Copy as Markdown
Other Tools
//! Pressure stall information retreived from `/proc/pressure/cpu`,
//! `/proc/pressure/memory` and `/proc/pressure/io`
//! may not be available on kernels older than 4.20.0
//!
use crate::{ProcError, ProcResult};
use std::collections::HashMap;
#[cfg(feature = "serde1")]
use serde::{Deserialize, Serialize};
/// Pressure stall information for either CPU, memory, or IO.
///
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
pub struct PressureRecord {
/// 10 second window
///
/// The percentage of time, over a 10 second window, that either some or all tasks were stalled
/// waiting for a resource.
pub avg10: f32,
/// 60 second window
///
/// The percentage of time, over a 60 second window, that either some or all tasks were stalled
/// waiting for a resource.
pub avg60: f32,
/// 300 second window
///
/// The percentage of time, over a 300 second window, that either some or all tasks were stalled
/// waiting for a resource.
pub avg300: f32,
/// Total stall time (in microseconds).
pub total: u64,
}
/// CPU pressure information
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
pub struct CpuPressure {
pub some: PressureRecord,
}
impl super::FromBufRead for CpuPressure {
fn from_buf_read<R: std::io::BufRead>(mut r: R) -> ProcResult<Self> {
let mut some = String::new();
r.read_line(&mut some)?;
Ok(CpuPressure {
some: parse_pressure_record(&some)?,
})
}
}
/// Memory pressure information
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
pub struct MemoryPressure {
/// This record indicates the share of time in which at least some tasks are stalled
pub some: PressureRecord,
/// This record indicates this share of time in which all non-idle tasks are stalled
/// simultaneously.
pub full: PressureRecord,
}
impl super::FromBufRead for MemoryPressure {
fn from_buf_read<R: std::io::BufRead>(r: R) -> ProcResult<Self> {
let (some, full) = get_pressure(r)?;
Ok(MemoryPressure { some, full })
}
}
/// IO pressure information
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
pub struct IoPressure {
/// This record indicates the share of time in which at least some tasks are stalled
pub some: PressureRecord,
/// This record indicates this share of time in which all non-idle tasks are stalled
/// simultaneously.
pub full: PressureRecord,
}
impl super::FromBufRead for IoPressure {
fn from_buf_read<R: std::io::BufRead>(r: R) -> ProcResult<Self> {
let (some, full) = get_pressure(r)?;
Ok(IoPressure { some, full })
}
}
fn get_f32(map: &HashMap<&str, &str>, value: &str) -> ProcResult<f32> {
map.get(value).map_or_else(
|| Err(ProcError::Incomplete(None)),
|v| v.parse::<f32>().map_err(|_| ProcError::Incomplete(None)),
)
}
fn get_total(map: &HashMap<&str, &str>) -> ProcResult<u64> {
map.get("total").map_or_else(
|| Err(ProcError::Incomplete(None)),
|v| v.parse::<u64>().map_err(|_| ProcError::Incomplete(None)),
)
}
fn parse_pressure_record(line: &str) -> ProcResult<PressureRecord> {
let mut parsed = HashMap::new();
if !line.starts_with("some") && !line.starts_with("full") {
return Err(ProcError::Incomplete(None));
}
let values = &line[5..];
for kv_str in values.split_whitespace() {
let kv_split = kv_str.split('=');
let vec: Vec<&str> = kv_split.collect();
if vec.len() == 2 {
parsed.insert(vec[0], vec[1]);
}
}
Ok(PressureRecord {
avg10: get_f32(&parsed, "avg10")?,
avg60: get_f32(&parsed, "avg60")?,
avg300: get_f32(&parsed, "avg300")?,
total: get_total(&parsed)?,
})
}
fn get_pressure<R: std::io::BufRead>(mut r: R) -> ProcResult<(PressureRecord, PressureRecord)> {
let mut some = String::new();
r.read_line(&mut some)?;
let mut full = String::new();
r.read_line(&mut full)?;
Ok((parse_pressure_record(&some)?, parse_pressure_record(&full)?))
}
#[cfg(test)]
mod test {
use super::*;
use std::f32::EPSILON;
#[test]
fn test_parse_pressure_record() {
let record = parse_pressure_record("full avg10=2.10 avg60=0.12 avg300=0.00 total=391926").unwrap();
assert!(record.avg10 - 2.10 < EPSILON);
assert!(record.avg60 - 0.12 < EPSILON);
assert!(record.avg300 - 0.00 < EPSILON);
assert_eq!(record.total, 391_926);
}
#[test]
fn test_parse_pressure_record_errs() {
assert!(parse_pressure_record("avg10=2.10 avg60=0.12 avg300=0.00 total=391926").is_err());
assert!(parse_pressure_record("some avg10=2.10 avg300=0.00 total=391926").is_err());
assert!(parse_pressure_record("some avg10=2.10 avg60=0.00 avg300=0.00").is_err());
}
}