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Avoid mem::uninitialized in the demo cpu_time
For both Unix `getrusage` and Windows `GetProcessTimes`, we can pass `MaybeUninit` pointers to those FFI calls and `assume_init()` afterward.
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Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -1,14 +1,17 @@ | ||
use libc::{getrusage, rusage, RUSAGE_SELF}; | ||
use std::mem; | ||
use libc::{getrusage, RUSAGE_SELF}; | ||
use std::mem::MaybeUninit; | ||
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||
pub fn get_cpu_time() -> Option<u64> { | ||
unsafe { | ||
let mut usage: rusage = mem::uninitialized(); | ||
getrusage(RUSAGE_SELF, &mut usage); | ||
let user = 1_000_000_000 * (usage.ru_utime.tv_sec as u64) | ||
+ 1_000 * (usage.ru_utime.tv_usec as u64); | ||
let system = 1_000_000_000 * (usage.ru_stime.tv_sec as u64) | ||
+ 1_000 * (usage.ru_stime.tv_usec as u64); | ||
Some(user + system) | ||
} | ||
let usage = unsafe { | ||
let mut usage = MaybeUninit::uninit(); | ||
if getrusage(RUSAGE_SELF, usage.as_mut_ptr()) != 0 { | ||
return None; | ||
} | ||
usage.assume_init() | ||
}; | ||
let user = | ||
1_000_000_000 * (usage.ru_utime.tv_sec as u64) + 1_000 * (usage.ru_utime.tv_usec as u64); | ||
let system = | ||
1_000_000_000 * (usage.ru_stime.tv_sec as u64) + 1_000 * (usage.ru_stime.tv_usec as u64); | ||
Some(user + system) | ||
} |
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Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -1,17 +1,26 @@ | ||
use std::mem; | ||
use winapi::shared::minwindef::FILETIME; | ||
use std::mem::MaybeUninit; | ||
use winapi::um::processthreadsapi::{GetCurrentProcess, GetProcessTimes}; | ||
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||
pub fn get_cpu_time() -> Option<u64> { | ||
unsafe { | ||
let (kernel, user) = unsafe { | ||
let process = GetCurrentProcess(); | ||
let mut _creation: FILETIME = mem::uninitialized(); | ||
let mut _exit: FILETIME = mem::uninitialized(); | ||
let mut kernel: FILETIME = mem::uninitialized(); | ||
let mut user: FILETIME = mem::uninitialized(); | ||
GetProcessTimes(process, &mut _creation, &mut _exit, &mut kernel, &mut user); | ||
let kernel = (kernel.dwHighDateTime as u64) << 32 | kernel.dwLowDateTime as u64; | ||
let user = (user.dwHighDateTime as u64) << 32 | user.dwLowDateTime as u64; | ||
Some(100 * (kernel + user)) | ||
} | ||
let mut _creation = MaybeUninit::uninit(); | ||
let mut _exit = MaybeUninit::uninit(); | ||
let mut kernel = MaybeUninit::uninit(); | ||
let mut user = MaybeUninit::uninit(); | ||
if GetProcessTimes( | ||
process, | ||
_creation.as_mut_ptr(), | ||
_exit.as_mut_ptr(), | ||
kernel.as_mut_ptr(), | ||
user.as_mut_ptr(), | ||
) == 0 | ||
{ | ||
return None; | ||
} | ||
(kernel.assume_init(), user.assume_init()) | ||
}; | ||
let kernel = (kernel.dwHighDateTime as u64) << 32 | kernel.dwLowDateTime as u64; | ||
let user = (user.dwHighDateTime as u64) << 32 | user.dwLowDateTime as u64; | ||
Some(100 * (kernel + user)) | ||
} |