Mercurial > hg > nginx-quic
view src/core/ngx_config.h @ 4621:c90801720a0c
Upstream: smooth weighted round-robin balancing.
For edge case weights like { 5, 1, 1 } we now produce { a, a, b, a, c, a, a }
sequence instead of { c, b, a, a, a, a, a } produced previously.
Algorithm is as follows: on each peer selection we increase current_weight
of each eligible peer by its weight, select peer with greatest current_weight
and reduce its current_weight by total number of weight points distributed
among peers.
In case of { 5, 1, 1 } weights this gives the following sequence of
current_weight's:
a b c
0 0 0 (initial state)
5 1 1 (a selected)
-2 1 1
3 2 2 (a selected)
-4 2 2
1 3 3 (b selected)
1 -4 3
6 -3 4 (a selected)
-1 -3 4
4 -2 5 (c selected)
4 -2 -2
9 -1 -1 (a selected)
2 -1 -1
7 0 0 (a selected)
0 0 0
To preserve weight reduction in case of failures the effective_weight
variable was introduced, which usually matches peer's weight, but is
reduced temporarily on peer failures.
This change also fixes loop with backup servers and proxy_next_upstream
http_404 (ticket #47), and skipping alive upstreams in some cases if there
are multiple dead ones (ticket #64).
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 14 May 2012 09:57:20 +0000 |
parents | d620f497c50f |
children | 626f288fa5ed |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_CONFIG_H_INCLUDED_ #define _NGX_CONFIG_H_INCLUDED_ #include <ngx_auto_headers.h> #if defined __DragonFly__ && !defined __FreeBSD__ #define __FreeBSD__ 4 #define __FreeBSD_version 480101 #endif #if (NGX_FREEBSD) #include <ngx_freebsd_config.h> #elif (NGX_LINUX) #include <ngx_linux_config.h> #elif (NGX_SOLARIS) #include <ngx_solaris_config.h> #elif (NGX_DARWIN) #include <ngx_darwin_config.h> #elif (NGX_WIN32) #include <ngx_win32_config.h> #else /* POSIX */ #include <ngx_posix_config.h> #endif #ifndef NGX_HAVE_SO_SNDLOWAT #define NGX_HAVE_SO_SNDLOWAT 1 #endif #if !(NGX_WIN32) #define ngx_signal_helper(n) SIG##n #define ngx_signal_value(n) ngx_signal_helper(n) #define ngx_random random /* TODO: #ifndef */ #define NGX_SHUTDOWN_SIGNAL QUIT #define NGX_TERMINATE_SIGNAL TERM #define NGX_NOACCEPT_SIGNAL WINCH #define NGX_RECONFIGURE_SIGNAL HUP #if (NGX_LINUXTHREADS) #define NGX_REOPEN_SIGNAL INFO #define NGX_CHANGEBIN_SIGNAL XCPU #else #define NGX_REOPEN_SIGNAL USR1 #define NGX_CHANGEBIN_SIGNAL USR2 #endif #define ngx_cdecl #define ngx_libc_cdecl #endif typedef intptr_t ngx_int_t; typedef uintptr_t ngx_uint_t; typedef intptr_t ngx_flag_t; #define NGX_INT32_LEN sizeof("-2147483648") - 1 #define NGX_INT64_LEN sizeof("-9223372036854775808") - 1 #if (NGX_PTR_SIZE == 4) #define NGX_INT_T_LEN NGX_INT32_LEN #else #define NGX_INT_T_LEN NGX_INT64_LEN #endif #ifndef NGX_ALIGNMENT #define NGX_ALIGNMENT sizeof(unsigned long) /* platform word */ #endif #define ngx_align(d, a) (((d) + (a - 1)) & ~(a - 1)) #define ngx_align_ptr(p, a) \ (u_char *) (((uintptr_t) (p) + ((uintptr_t) a - 1)) & ~((uintptr_t) a - 1)) #define ngx_abort abort /* TODO: platform specific: array[NGX_INVALID_ARRAY_INDEX] must cause SIGSEGV */ #define NGX_INVALID_ARRAY_INDEX 0x80000000 /* TODO: auto_conf: ngx_inline inline __inline __inline__ */ #ifndef ngx_inline #define ngx_inline inline #endif #ifndef INADDR_NONE /* Solaris */ #define INADDR_NONE ((unsigned int) -1) #endif #ifdef MAXHOSTNAMELEN #define NGX_MAXHOSTNAMELEN MAXHOSTNAMELEN #else #define NGX_MAXHOSTNAMELEN 256 #endif #if ((__GNU__ == 2) && (__GNUC_MINOR__ < 8)) #define NGX_MAX_UINT32_VALUE (uint32_t) 0xffffffffLL #else #define NGX_MAX_UINT32_VALUE (uint32_t) 0xffffffff #endif #define NGX_MAX_INT32_VALUE (uint32_t) 0x7fffffff #endif /* _NGX_CONFIG_H_INCLUDED_ */