[PATCH] The auto parameter of the worker_processes supports to detect the container environment.

[Maxim Dounin]

Hello!

On Wed, Apr 25, 2018 at 12:47:13AM +0800, agile6v wrote:

> # HG changeset patch
> # User Agile6v <agile6v at agile6v.com>
> # Date 1524585905 -28800
> #      Wed Apr 25 00:05:05 2018 +0800
> # Node ID 89793df28d1bcf2baf00e389e6806d32d7435886
> # Parent  7c614ef3c6ea330c62630d5065f961a27d0f82cd
> The auto parameter of the worker_processes supports to detect the container environment.
> 
> 
> Docker mounts cgroup information into container starting with version 1.8,
> so it is possible to determine the appropriate number of CPUs based on the 
> cgroup information in the container. Refer to JDK related implementation:
> https://bugs.openjdk.java.net/browse/JDK-8146115
> 
> 
> diff -r 7c614ef3c6ea -r 89793df28d1b auto/sources
> --- a/auto/sources	Wed Apr 18 16:11:41 2018 +0300
> +++ b/auto/sources	Wed Apr 25 00:05:05 2018 +0800
> @@ -192,8 +192,8 @@
>  FREEBSD_SRCS=src/os/unix/ngx_freebsd_init.c
>  FREEBSD_SENDFILE_SRCS=src/os/unix/ngx_freebsd_sendfile_chain.c
>  
> -LINUX_DEPS="src/os/unix/ngx_linux_config.h src/os/unix/ngx_linux.h"
> -LINUX_SRCS=src/os/unix/ngx_linux_init.c
> +LINUX_DEPS="src/os/unix/ngx_linux_config.h src/os/unix/ngx_linux.h src/os/unix/ngx_container.h"
> +LINUX_SRCS="src/os/unix/ngx_linux_init.c src/os/unix/ngx_container.c"
>  LINUX_SENDFILE_SRCS=src/os/unix/ngx_linux_sendfile_chain.c
>  
>  
> diff -r 7c614ef3c6ea -r 89793df28d1b src/os/unix/ngx_container.c
> --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
> +++ b/src/os/unix/ngx_container.c	Wed Apr 25 00:05:05 2018 +0800
> @@ -0,0 +1,418 @@
> +
> +/*
> + * Copyright (C) agile6v
> + * Copyright (C) Xiaomi, Inc.
> + */
> +
> +#include <ngx_config.h>
> +#include <ngx_core.h>
> +
> +#define NGX_BUFFER_SIZE     8192
> +#define PER_CPU_SHARES      1024
> +
> +typedef struct {
> +    ngx_str_t root;
> +    ngx_str_t path;
> +    ngx_str_t mount_point;
> +} cgroup_subsystem_info;
> +
> +static cgroup_subsystem_info cpu_subsystem;
> +
> +static ngx_str_t proc_cgroup_file   = ngx_string("/proc/self/cgroup");
> +static ngx_str_t proc_mount_file    = ngx_string("/proc/self/mountinfo");
> +static ngx_str_t cpu_cfs_period     = ngx_string("/cpu.cfs_period_us");
> +static ngx_str_t cpu_cfs_quota      = ngx_string("/cpu.cfs_quota_us");
> +static ngx_str_t cpu_cfs_shares     = ngx_string("/cpu.shares");

[...]

400+ lines of code to obtain a number which is expected to be 
directly available via the sysconf(_SC_NPROCESSORS_ONLN) call 
might be a bit too many.

Thank you for your effort, but no.

-- 
Maxim Dounin
http://mdounin.ru/