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view auto/os/conf @ 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 | d91f3c78603e |
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# Copyright (C) Igor Sysoev # Copyright (C) Nginx, Inc. echo "checking for $NGX_SYSTEM specific features" case "$NGX_PLATFORM" in FreeBSD:*) . auto/os/freebsd ;; Linux:*) . auto/os/linux ;; SunOS:*) . auto/os/solaris ;; Darwin:*) . auto/os/darwin ;; win32) . auto/os/win32 ;; DragonFly:*) have=NGX_FREEBSD . auto/have_headers CORE_INCS="$UNIX_INCS" CORE_DEPS="$UNIX_DEPS $FREEBSD_DEPS" CORE_SRCS="$UNIX_SRCS $FREEBSD_SRCS" echo " + sendfile() found" have=NGX_HAVE_SENDFILE . auto/have CORE_SRCS="$CORE_SRCS $FREEBSD_SENDFILE_SRCS" ngx_spacer=' ' ;; HP-UX:*) # HP/UX have=NGX_HPUX . auto/have_headers CORE_INCS="$UNIX_INCS" CORE_DEPS="$UNIX_DEPS $POSIX_DEPS" CORE_SRCS="$UNIX_SRCS" CC_AUX_FLAGS="$CC_AUX_FLAGS -D_XOPEN_SOURCE -D_XOPEN_SOURCE_EXTENDED=1" ;; OSF1:*) # Tru64 UNIX have=NGX_TRU64 . auto/have_headers have=NGX_HAVE_STRERROR_R . auto/nohave CORE_INCS="$UNIX_INCS" CORE_DEPS="$UNIX_DEPS $POSIX_DEPS" CORE_SRCS="$UNIX_SRCS" ;; *) CORE_INCS="$UNIX_INCS" CORE_DEPS="$UNIX_DEPS $POSIX_DEPS" CORE_SRCS="$UNIX_SRCS" ;; esac case "$NGX_MACHINE" in i386 | i686 | i86pc) have=NGX_HAVE_NONALIGNED . auto/have NGX_MACH_CACHE_LINE=32 ;; amd64 | x86_64) have=NGX_HAVE_NONALIGNED . auto/have NGX_MACH_CACHE_LINE=64 ;; sun4u | sun4v | sparc | sparc64) have=NGX_ALIGNMENT value=16 . auto/define # TODO NGX_MACH_CACHE_LINE=64 ;; ia64 ) have=NGX_ALIGNMENT value=16 . auto/define # TODO NGX_MACH_CACHE_LINE=64 ;; *) NGX_MACH_CACHE_LINE=32 ;; esac if test -z "$NGX_CPU_CACHE_LINE"; then NGX_CPU_CACHE_LINE=$NGX_MACH_CACHE_LINE fi have=NGX_CPU_CACHE_LINE value=$NGX_CPU_CACHE_LINE . auto/define