view auto/cc/clang @ 8398:82e174e47663

Changed keepalive_requests default to 1000 (ticket #2155). It turns out no browsers implement HTTP/2 GOAWAY handling properly, and large enough number of resources on a page results in failures to load some resources. In particular, Chrome seems to experience errors if loading of all resources requires more than 1 connection (while it is usually able to retry requests at least once, even with 2 connections there are occasional failures for some reason), Safari if loading requires more than 3 connections, and Firefox if loading requires more than 10 connections (can be configured with network.http.request.max-attempts, defaults to 10). It does not seem to be possible to resolve this on nginx side, even strict limiting of maximum concurrency does not help, and loading issues seems to be triggered by merely queueing of a request for a particular connection. The only available mitigation seems to use higher keepalive_requests value. The new default is 1000 and matches previously used default for http2_max_requests. It is expected to be enough for 99.98% of the pages (https://httparchive.org/reports/state-of-the-web?start=latest#reqTotal) even in Chrome.
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 08 Apr 2021 00:16:30 +0300
parents ceab908790c4
children
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# Copyright (C) Nginx, Inc.


# clang


NGX_CLANG_VER=`$CC -v 2>&1 | grep 'version' 2>&1 \
                           | sed -n -e 's/^.*clang version \(.*\)/\1/p' \
                                    -e 's/^.*LLVM version \(.*\)/\1/p'`

echo " + clang version: $NGX_CLANG_VER"

have=NGX_COMPILER value="\"clang $NGX_CLANG_VER\"" . auto/define


CC_TEST_FLAGS="-pipe"


# optimizations

#NGX_CLANG_OPT="-O2"
#NGX_CLANG_OPT="-Oz"
NGX_CLANG_OPT="-O"

case $CPU in
    pentium)
        # optimize for Pentium
        CPU_OPT="-march=pentium"
        NGX_CPU_CACHE_LINE=32
    ;;

    pentiumpro | pentium3)
        # optimize for Pentium Pro, Pentium II and Pentium III
        CPU_OPT="-march=pentiumpro"
        NGX_CPU_CACHE_LINE=32
    ;;

    pentium4)
        # optimize for Pentium 4
        CPU_OPT="-march=pentium4"
        NGX_CPU_CACHE_LINE=128
    ;;

    athlon)
        # optimize for Athlon
        CPU_OPT="-march=athlon"
        NGX_CPU_CACHE_LINE=64
    ;;

    opteron)
        # optimize for Opteron
        CPU_OPT="-march=opteron"
        NGX_CPU_CACHE_LINE=64
    ;;

esac

CC_AUX_FLAGS="$CC_AUX_FLAGS $CPU_OPT"


CFLAGS="$CFLAGS -pipe $CPU_OPT"

if [ ".$PCRE_OPT" = "." ]; then
    PCRE_OPT="-O2 -pipe $CPU_OPT"
else
    PCRE_OPT="$PCRE_OPT -pipe"
fi

if [ ".$ZLIB_OPT" = "." ]; then
    ZLIB_OPT="-O2 -pipe $CPU_OPT"
else
    ZLIB_OPT="$ZLIB_OPT -pipe"
fi


# warnings

CFLAGS="$CFLAGS $NGX_CLANG_OPT -Wall -Wextra -Wpointer-arith"
CFLAGS="$CFLAGS -Wconditional-uninitialized"
#CFLAGS="$CFLAGS -Wmissing-prototypes"

# we have a lot of unused function arguments
CFLAGS="$CFLAGS -Wno-unused-parameter"

# deprecated system OpenSSL library on OS X
if [ "$NGX_SYSTEM" = "Darwin" ]; then
    CFLAGS="$CFLAGS -Wno-deprecated-declarations"
fi

# stop on warning
CFLAGS="$CFLAGS -Werror"

# debug
CFLAGS="$CFLAGS -g"

if [ ".$CPP" = "." ]; then
    CPP="$CC -E"
fi