view auto/cc/conf @ 7281:bd6563e81cea

Limit req: improved handling of negative times. Negative times can appear since workers only update time on an event loop iteration start. If a worker was blocked for a long time during an event loop iteration, it is possible that another worker already updated the time stored in the node. As such, time since last update of the node (ms) will be negative. Previous code used ngx_abs(ms) in the calculations. That is, negative times were effectively treated as positive ones. As a result, it was not possible to maintain high request rates, where the same node can be updated multiple times from during an event loop iteration. In particular, this affected setups with many SSL handshakes, see http://mailman.nginx.org/pipermail/nginx/2018-May/056291.html. Fix is to only update the last update time stored in the node if the new time is larger than previously stored one. If a future time is stored in the node, we preserve this time as is. To prevent breaking things on platforms without monotonic time available if system time is updated backwards, a safety limit of 60 seconds is used. If the time stored in the node is more than 60 seconds in the future, we assume that the time was changed backwards and update lr->last to the current time.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 30 May 2018 15:40:34 +0300
parents 4925a6d13746
children 9bcc5cc94ff4
line wrap: on
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# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


LINK="\$(CC)"

MAIN_LINK=
MODULE_LINK="-shared"

ngx_include_opt="-I "
ngx_compile_opt="-c"
ngx_pic_opt="-fPIC"
ngx_objout="-o "
ngx_binout="-o "
ngx_objext="o"
ngx_binext=
ngx_modext=".so"

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"
        ;;

        sunc)

            MAIN_LINK=
            MODULE_LINK="-G"

            case "$NGX_MACHINE" in

                i86pc)
                    NGX_AUX=" src/os/unix/ngx_sunpro_x86.il"
                ;;

                sun4u | sun4v)
                    NGX_AUX=" src/os/unix/ngx_sunpro_sparc64.il"
                ;;

            esac

            case $CPU in

                amd64)
                    NGX_AUX=" src/os/unix/ngx_sunpro_amd64.il"
                ;;

            esac
        ;;

    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
        ;;

        clang)
            # Clang C compiler

            . auto/cc/clang
        ;;

        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="-Wl,-E switch"
    ngx_feature_name=
    ngx_feature_run=no
    ngx_feature_incs=
    ngx_feature_path=
    ngx_feature_libs=-Wl,-E
    ngx_feature_test=
    . auto/feature

    if [ $ngx_found = yes ]; then
        MAIN_LINK="-Wl,-E"
    fi


    if [ "$NGX_CC_NAME" = "sunc" ]; then
        echo "checking for gcc builtin atomic operations ... disabled"
    else
        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
    fi


    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="gcc builtin 64 bit byteswap"
    ngx_feature_name="NGX_HAVE_GCC_BSWAP64"
    ngx_feature_run=no
    ngx_feature_incs=
    ngx_feature_path=
    ngx_feature_libs=
    ngx_feature_test="if (__builtin_bswap64(0)) 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