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