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view auto/cc/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 | 182aee3b1bf5 |
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# Copyright (C) Igor Sysoev # Copyright (C) Nginx, Inc. LINK="\$(CC)" ngx_include_opt="-I " ngx_compile_opt="-c" ngx_objout="-o " ngx_binout="-o " ngx_objext="o" ngx_binext= ngx_long_start= ngx_long_end= ngx_regex_dirsep="\/" ngx_dirsep='/' ngx_regex_cont=' \\\ ' ngx_cont=' \ ' ngx_tab=' \ ' ngx_spacer= ngx_long_regex_cont=$ngx_regex_cont ngx_long_cont=$ngx_cont . auto/cc/name if test -n "$CFLAGS"; then CC_TEST_FLAGS="$CFLAGS $NGX_CC_OPT" case $NGX_CC_NAME in ccc) # Compaq C V6.5-207 ngx_include_opt="-I" ;; esac else case $NGX_CC_NAME in gcc) # gcc 2.7.2.3, 2.8.1, 2.95.4, egcs-1.1.2 # 3.0.4, 3.1.1, 3.2.3, 3.3.2, 3.3.3, 3.3.4, 3.4.0, 3.4.2 # 4.0.0, 4.0.1, 4.1.0 . auto/cc/gcc ;; icc) # Intel C++ compiler 7.1, 8.0, 8.1 . auto/cc/icc ;; sunc) # Sun C 5.7 Patch 117837-04 2005/05/11 . auto/cc/sunc ;; ccc) # Compaq C V6.5-207 . auto/cc/ccc ;; acc) # aCC: HP ANSI C++ B3910B A.03.55.02 . auto/cc/acc ;; msvc*) # MSVC++ 6.0 SP2, MSVC++ Toolkit 2003 . auto/cc/msvc ;; owc) # Open Watcom C 1.0, 1.2 . auto/cc/owc ;; bcc) # Borland C++ 5.5 . auto/cc/bcc ;; esac CC_TEST_FLAGS="$CC_TEST_FLAGS $NGX_CC_OPT" fi CFLAGS="$CFLAGS $NGX_CC_OPT" NGX_TEST_LD_OPT="$NGX_LD_OPT" if [ "$NGX_PLATFORM" != win32 ]; then if test -n "$NGX_LD_OPT"; then ngx_feature=--with-ld-opt=\"$NGX_LD_OPT\" ngx_feature_name= ngx_feature_run=no ngx_feature_incs= ngx_feature_path= ngx_feature_libs= ngx_feature_test= . auto/feature if [ $ngx_found = no ]; then echo $0: error: the invalid value in --with-ld-opt=\"$NGX_LD_OPT\" echo exit 1 fi fi ngx_feature="gcc builtin atomic operations" ngx_feature_name=NGX_HAVE_GCC_ATOMIC ngx_feature_run=yes ngx_feature_incs= ngx_feature_path= ngx_feature_libs= ngx_feature_test="long n = 0; if (!__sync_bool_compare_and_swap(&n, 0, 1)) return 1; if (__sync_fetch_and_add(&n, 1) != 1) return 1; if (n != 2) return 1; __sync_synchronize();" . auto/feature if [ "$NGX_CC_NAME" = "ccc" ]; then echo "checking for C99 variadic macros ... disabled" else ngx_feature="C99 variadic macros" ngx_feature_name="NGX_HAVE_C99_VARIADIC_MACROS" ngx_feature_run=yes ngx_feature_incs="#include <stdio.h> #define var(dummy, ...) sprintf(__VA_ARGS__)" ngx_feature_path= ngx_feature_libs= ngx_feature_test="char buf[30]; buf[0] = '0'; var(0, buf, \"%d\", 1); if (buf[0] != '1') return 1" . auto/feature fi ngx_feature="gcc variadic macros" ngx_feature_name="NGX_HAVE_GCC_VARIADIC_MACROS" ngx_feature_run=yes ngx_feature_incs="#include <stdio.h> #define var(dummy, args...) sprintf(args)" ngx_feature_path= ngx_feature_libs= ngx_feature_test="char buf[30]; buf[0] = '0'; var(0, buf, \"%d\", 1); if (buf[0] != '1') return 1" . auto/feature # ngx_feature="inline" # ngx_feature_name= # ngx_feature_run=no # ngx_feature_incs="int inline f(void) { return 1 }" # ngx_feature_path= # ngx_feature_libs= # ngx_feature_test= # . auto/feature # # if [ $ngx_found = yes ]; then # fi fi