Rust

Env::args()

Brief

A naive attempt at optimizing a simple ipv4 address checker using env::args()

Assumptions

Cargo.tml

[profile.release]
strip = "symbols"
debug = 0
opt-level = "z"
lto = true
codegen-units = 1
panic = "abort"

Unoptimized

• Stores args as an immutable (imut) string vector
• Stores ip_addr as imut string then shadows as imut string slice vector
• Uses len() calls for no real reason

main.rsstrace

use std::env;

fn main() {
    let args: Vec<String> = env::args().collect();
    if args.len() > 1 {
        let ip_addr: String = args[1].to_string();
        let ip_addr: Vec<&str> = ip_addr.split('.').collect();
        if ip_addr.len() == 4 {
            for octect in ip_addr {
                octect.parse::<u8>().expect(&format!("invalid ip"));
            }
        } else {
            panic!("invalid ip")
        }
    }
}

~/workspace/ipcheck> sha256sum src/main.rs
4cb6865ea743c3a2cee6e05966e117b8db51f32cb55de6baad205196bbc4195d  src/main.rs

~/workspace/ipcheck> cargo build --release
Compiling ipcheck v0.1.0 (/home/lost/workspace/ipcheck)
    Finished `release` profile [optimized] target(s) in 2.93s

~/workspace/ipcheck> strace -c ./target/release/ipcheck 1.1.1.1
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ------------------
37.07    0.000470         470         1           execve
14.43    0.000183          14        13           mmap
8.52    0.000108          21         5           read
7.10    0.000090          15         6           mprotect
6.78    0.000086          21         4           openat
3.63    0.000046          23         2           munmap
3.08    0.000039           9         4           newfstatat
2.76    0.000035          11         3           brk
2.60    0.000033           6         5           rt_sigaction
2.52    0.000032           8         4           close
2.37    0.000030           7         4           pread64
1.50    0.000019           6         3           sigaltstack
1.34    0.000017          17         1         1 access
1.34    0.000017           8         2           prlimit64
1.10    0.000014           7         2         1 arch_prctl
1.03    0.000013          13         1           poll
0.71    0.000009           9         1           sched_getaffinity
0.63    0.000008           8         1           getrandom
0.55    0.000007           7         1           set_tid_address
0.47    0.000006           6         1           set_robust_list
0.47    0.000006           6         1           rseq
------ ----------- ----------- --------- --------- ------------------
100.00    0.001268          19        65         2 total

Optimized

• Needs some cleanup
• Needs break for args after index 1

main.rsstrace

use std::env;

fn main() {
    for (index, arg) in env::args().enumerate(){
        if index == 1 {
            for (i, octect) in arg.split('.').collect::<Vec<&str>>().iter().enumerate() {
                if i > 3 {
                    panic!("invalid")
                } else {
                    let _ = &octect.parse::<u8>().expect("invalid");
                }
            }
        }
    }
}

~/workspace/ipcheck> sha256sum src/main.rs
838b3f0c99448e8bbe88001de4d12f5062d293a2a1fd236deacfabdb30a7e2e4  src/main.rs

~/workspace/ipcheck> cargo build --release
Compiling ipcheck v0.1.0 (/home/lost/workspace/ipcheck)
    Finished `release` profile [optimized] target(s) in 2.89s

~/workspace/ipcheck> strace -c ./target/release/ipcheck 1.1.1.1                                                                                                                      06/22/2024 07:57:31 PM
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ------------------
23.07    0.000161          12        13           mmap
15.33    0.000107          21         5           read
13.04    0.000091          15         6           mprotect
10.17    0.000071          17         4           openat
6.73    0.000047          23         2           munmap
4.87    0.000034           6         5           rt_sigaction
4.01    0.000028           7         4           pread64
4.01    0.000028           7         4           newfstatat
3.72    0.000026           6         4           close
2.87    0.000020           6         3           sigaltstack
2.15    0.000015           5         3           brk
2.01    0.000014          14         1           poll
1.86    0.000013           6         2           prlimit64
1.29    0.000009           9         1           sched_getaffinity
1.15    0.000008           8         1           getrandom
1.00    0.000007           3         2         1 arch_prctl
1.00    0.000007           7         1           set_tid_address
0.86    0.000006           6         1           set_robust_list
0.86    0.000006           6         1           rseq
0.00    0.000000           0         1         1 access
0.00    0.000000           0         1           execve
------ ----------- ----------- --------- --------- ------------------
100.00    0.000698          10        65         2 total