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Minor changes to improve compilation speed #137

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4f7d6d8
Partially document current MSRV
Aeledfyr Feb 25, 2024
b63550c
Remove unnecessary internal generic parameter
Aeledfyr Feb 25, 2024
ff5dbc9
Optimize compilation time of parsing functions on Linux
Aeledfyr Feb 25, 2024
5c6c743
Prevent debug macro from generating format_args when not in use
Aeledfyr Feb 25, 2024
a0fbf43
Use Vec instead of HashMap when counting physical cores
Aeledfyr Feb 25, 2024
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1 change: 1 addition & 0 deletions Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@

name = "num_cpus"
version = "1.16.0"
rust-version = "1.13"
description = "Get the number of CPUs on a machine."
authors = ["Sean McArthur <[email protected]>"]
license = "MIT OR Apache-2.0"
Expand Down
122 changes: 69 additions & 53 deletions src/linux.rs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,3 @@
use std::collections::HashMap;
use std::fs::File;
use std::io::{BufRead, BufReader, Read};
use std::mem;
Expand All @@ -9,13 +8,13 @@ use std::sync::Once;
use libc;

macro_rules! debug {
($($args:expr),*) => ({
if false {
//if true {
println!($($args),*);
}
});
($($args:tt)*) => ({});
}
// macro_rules! debug {
// ($($args:expr),*) => ({
// println!($($args),*);
// });
// }

macro_rules! some {
($e:expr) => {{
Expand Down Expand Up @@ -62,36 +61,51 @@ pub fn get_num_physical_cpus() -> usize {
Err(_) => return get_num_cpus(),
};
let reader = BufReader::new(file);
let mut map = HashMap::new();
let mut core_list = Vec::new();
let mut physid: u32 = 0;
let mut cores: usize = 0;
let mut chgcount = 0;
for line in reader.lines().filter_map(|result| result.ok()) {
for line in reader.lines() {
let line = if let Ok(l) = line { l } else { continue };

let mut it = line.split(':');
let (key, value) = match (it.next(), it.next()) {
(Some(key), Some(value)) => (key.trim(), value.trim()),
_ => continue,
};
if key == "physical id" {
match value.parse() {
Ok(val) => physid = val,
Err(_) => break,
};
chgcount += 1;
}
if key == "cpu cores" {
match value.parse() {
Ok(val) => cores = val,
Err(_) => break,
};
chgcount += 1;
match key {
"physical id" => {
match value.parse() {
Ok(val) => physid = val,
Err(_) => break,
};
chgcount += 1;
}
"cpu cores" => {
match value.parse() {
Ok(val) => cores = val,
Err(_) => break,
};
chgcount += 1;
}
_ => (),
}

if chgcount == 2 {
map.insert(physid, cores);
core_list.push((physid, cores));
chgcount = 0;
}
}
let count = map.into_iter().fold(0, |acc, (_, cores)| acc + cores);

core_list.sort_by_key(|&(id, _)| id);

let mut count = 0;
let mut prev = None;
for (id, cores) in core_list {
if prev == Some(id) { continue }
prev = Some(id);
count += cores;
}

if count == 0 {
get_num_cpus()
Expand Down Expand Up @@ -131,7 +145,7 @@ fn init_cgroups() {
return;
}

if let Some(quota) = load_cgroups("/proc/self/cgroup", "/proc/self/mountinfo") {
if let Some(quota) = load_cgroups("/proc/self/cgroup".as_ref(), "/proc/self/mountinfo".as_ref()) {
if quota == 0 {
return;
}
Expand All @@ -143,11 +157,7 @@ fn init_cgroups() {
}
}

fn load_cgroups<P1, P2>(cgroup_proc: P1, mountinfo_proc: P2) -> Option<usize>
where
P1: AsRef<Path>,
P2: AsRef<Path>,
{
fn load_cgroups(cgroup_proc: &Path, mountinfo_proc: &Path) -> Option<usize> {
let subsys = some!(Subsys::load_cpu(cgroup_proc));
let mntinfo = some!(MountInfo::load_cpu(mountinfo_proc, subsys.version));
let cgroup = some!(Cgroup::translate(mntinfo, subsys));
Expand Down Expand Up @@ -250,14 +260,20 @@ impl Cgroup {
}

impl MountInfo {
fn load_cpu<P: AsRef<Path>>(proc_path: P, version: CgroupVersion) -> Option<MountInfo> {
fn load_cpu(proc_path: &Path, version: CgroupVersion) -> Option<MountInfo> {
let file = some!(File::open(proc_path).ok());
let file = BufReader::new(file);

file.lines()
.filter_map(|result| result.ok())
.filter_map(MountInfo::parse_line)
.find(|mount_info| mount_info.version == version)
for line in file.lines() {
let mount_info = line.ok().and_then(MountInfo::parse_line);

if let Some(mount_info) = mount_info {
if mount_info.version == version {
return Some(mount_info);
}
}
}
None
}

fn parse_line(line: String) -> Option<MountInfo> {
Expand Down Expand Up @@ -305,21 +321,21 @@ impl MountInfo {
}

impl Subsys {
fn load_cpu<P: AsRef<Path>>(proc_path: P) -> Option<Subsys> {
fn load_cpu(proc_path: &Path) -> Option<Subsys> {
let file = some!(File::open(proc_path).ok());
let file = BufReader::new(file);

file.lines()
.filter_map(|result| result.ok())
.filter_map(Subsys::parse_line)
.fold(None, |previous, line| {
// already-found v1 trumps v2 since it explicitly specifies its controllers
if previous.is_some() && line.version == CgroupVersion::V2 {
return previous;
}
let mut current = None;
for line in file.lines() {
let line = line.ok().and_then(Subsys::parse_line);
let line = if let Some(l) = line { l } else { continue };

Some(line)
})
// v1 trumps v2 since it explicitly specifies its controllers
if current.is_none() || line.version == CgroupVersion::V1 {
current = Some(line);
}
}
current
}

fn parse_line(line: String) -> Option<Subsys> {
Expand Down Expand Up @@ -369,23 +385,23 @@ mod tests {
// test only one optional fields
let path = join!(FIXTURES_PROC, "mountinfo");

let mnt_info = MountInfo::load_cpu(path, CgroupVersion::V1).unwrap();
let mnt_info = MountInfo::load_cpu(&path, CgroupVersion::V1).unwrap();

assert_eq!(mnt_info.root, "/");
assert_eq!(mnt_info.mount_point, "/sys/fs/cgroup/cpu,cpuacct");

// test zero optional field
let path = join!(FIXTURES_PROC, "mountinfo_zero_opt");

let mnt_info = MountInfo::load_cpu(path, CgroupVersion::V1).unwrap();
let mnt_info = MountInfo::load_cpu(&path, CgroupVersion::V1).unwrap();

assert_eq!(mnt_info.root, "/");
assert_eq!(mnt_info.mount_point, "/sys/fs/cgroup/cpu,cpuacct");

// test multi optional fields
let path = join!(FIXTURES_PROC, "mountinfo_multi_opt");

let mnt_info = MountInfo::load_cpu(path, CgroupVersion::V1).unwrap();
let mnt_info = MountInfo::load_cpu(&path, CgroupVersion::V1).unwrap();

assert_eq!(mnt_info.root, "/");
assert_eq!(mnt_info.mount_point, "/sys/fs/cgroup/cpu,cpuacct");
Expand All @@ -395,7 +411,7 @@ mod tests {
fn test_load_subsys() {
let path = join!(FIXTURES_PROC, "cgroup");

let subsys = Subsys::load_cpu(path).unwrap();
let subsys = Subsys::load_cpu(&path).unwrap();

assert_eq!(subsys.base, "/");
assert_eq!(subsys.version, CgroupVersion::V1);
Expand Down Expand Up @@ -494,7 +510,7 @@ mod tests {
// test only one optional fields
let path = join!(FIXTURES_PROC, "mountinfo");

let mnt_info = MountInfo::load_cpu(path, CgroupVersion::V2).unwrap();
let mnt_info = MountInfo::load_cpu(&path, CgroupVersion::V2).unwrap();

assert_eq!(mnt_info.root, "/");
assert_eq!(mnt_info.mount_point, "/sys/fs/cgroup");
Expand All @@ -504,7 +520,7 @@ mod tests {
fn test_load_subsys() {
let path = join!(FIXTURES_PROC, "cgroup");

let subsys = Subsys::load_cpu(path).unwrap();
let subsys = Subsys::load_cpu(&path).unwrap();

assert_eq!(subsys.base, "/");
assert_eq!(subsys.version, CgroupVersion::V2);
Expand All @@ -514,7 +530,7 @@ mod tests {
fn test_load_subsys_multi() {
let path = join!(FIXTURES_PROC, "cgroup_multi");

let subsys = Subsys::load_cpu(path).unwrap();
let subsys = Subsys::load_cpu(&path).unwrap();

assert_eq!(subsys.base, "/");
assert_eq!(subsys.version, CgroupVersion::V1);
Expand Down