英文:
Golang Getrlimit returns the different value from ulimit
问题
我尝试使用Golang的Getrlimit函数获取当前的“打开文件描述符”限制。以下是我的代码：
package main
import (
"fmt"
"syscall"
)
func main() {
lim := syscall.Rlimit{}
err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim)
if err != nil {
panic(err)
}
fmt.Println("soft:", lim.Cur)
fmt.Println("hard:", lim.Max)
}
运行这段代码会输出：
$ go run main.go
soft: 1048576
hard: 1048576
你可以看到软限制（soft）的值是"1048576"，然而，使用ulimit -Sn命令输出的值是"1024"。我还尝试了使用以下C代码：
#include <sys/resource.h>
#include <stdio.h>
int main() {
struct rlimit rlim;
if (getrlimit(RLIMIT_NOFILE, &rlim) == -1) {
return -1;
}
printf("soft: %lld \n", (long long) rlim.rlim_cur);
printf("hard: %lld \n", (long long) rlim.rlim_max);
return 0;
}
编译并运行这段代码也会输出：
soft: 1024
hard: 1048576
所以，Golang打印出的"rlim_max"（硬限制）的值是正确的，但"rlim_cur"（软限制）的值是不正确的，它应该是"1024"。正如你所看到的，C代码和ulimit -Sn命令都输出了"1024"。
这是我的测试环境：
- 操作系统：Ubuntu 22.04 LTS x86_64
- Golang 1.19.1 for amd64
我想知道是否有人遇到了相同的问题，以及为什么会出现这种情况？谢谢！
英文:
I tried to use Golang to get current "open fd" limit with the Getrlimit function, here is my code:
package main
import (
"fmt"
"syscall"
)
func main() {
lim := syscall.Rlimit{}
err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim)
if err != nil {
panic(err)
}
fmt.Println("soft:", lim.Cur)
fmt.Println("hard:", lim.Max)
}
Run this will print:
$ go run main.go
soft: 1048576
hard: 1048576
Here you can see the soft number is "1048576", however, the ulimit -Sn prints it as "1024". I also tried this with C code:
#include <sys/resource.h>
#include <stdio.h>
int main() {
struct rlimit rlim;
if (getrlimit(RLIMIT_NOFILE, &rlim) == -1) {
return -1;
}
printf("soft: %lld \n", (long long) rlim.rlim_cur);
printf("hard: %lld \n", (long long) rlim.rlim_max);
return 0;
}
Compile and run it will also print:
soft: 1024
hard: 1048576
So the number Golang printed out for the "rlim_max" (hard) is correct, but "rlim_cur" (soft) is incorrect, it's supposed to be "1024"? As you can see both the C code and ulimit -Sn command printed "1024".
Here is my testing environment:
- Operating system: Ubuntu 22.04 LTS x86_64
- Golang 1.19.1 for amd64
I am wondering if anyone experienced the same problem and why it happened like this? Thank you!
答案1
得分: 0
这是根据1.19版本的设计，详细讨论请参考https://github.com/golang/go/issues/46279。
英文:
This is per design since 1.19, see https://github.com/golang/go/issues/46279 for the whole discussion.
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