view auto/cc/gcc @ 9138:a90f79792b5d

QUIC: optimized ACK delay. Previously ACK was not generated if max_ack_delay was not yet expired and the number of unacknowledged ack-eliciting packets was less than two, as allowed by RFC 9000 13.2.1-13.2.2. However this only makes sense to avoid sending ACK-only packets, as explained by the RFC: On the other hand, reducing the frequency of packets that carry only acknowledgments reduces packet transmission and processing cost at both endpoints. Now ACK is delayed only if output frame queue is empty. Otherwise ACK is sent immediately, which significantly improves QUIC performance with certain tests.
author Roman Arutyunyan <arut@nginx.com>
date Thu, 27 Jul 2023 16:37:17 +0400
parents 9eefb38f0005
children
line wrap: on
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# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


# 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


NGX_GCC_VER=`$CC -v 2>&1 | grep 'gcc version' 2>&1 \
                         | sed -e 's/^.* version \(.*\)/\1/'`

echo " + gcc version: $NGX_GCC_VER"

have=NGX_COMPILER value="\"gcc $NGX_GCC_VER\"" . auto/define


# Solaris 7's /usr/ccs/bin/as does not support "-pipe"

CC_TEST_FLAGS="-pipe"

ngx_feature="gcc -pipe switch"
ngx_feature_name=
ngx_feature_run=no
ngx_feature_incs=
ngx_feature_path=
ngx_feature_libs=
ngx_feature_test=
. auto/feature

CC_TEST_FLAGS=

if [ $ngx_found = yes ]; then
    PIPE="-pipe"
fi


case "$NGX_MACHINE" in

    sun4u | sun4v | sparc | sparc64 )
        # "-mcpu=v9" enables the "casa" assembler instruction
        CFLAGS="$CFLAGS -mcpu=v9"
    ;;

esac


# optimizations

#NGX_GCC_OPT="-O2"
#NGX_GCC_OPT="-Os"
NGX_GCC_OPT="-O"

#CFLAGS="$CFLAGS -fomit-frame-pointer"

case $CPU in
    pentium)
        # optimize for Pentium and Athlon
        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, gcc 3.x
        CPU_OPT="-march=pentium4"
        NGX_CPU_CACHE_LINE=128
    ;;

    athlon)
        # optimize for Athlon, gcc 3.x
        CPU_OPT="-march=athlon"
        NGX_CPU_CACHE_LINE=64
    ;;

    opteron)
        # optimize for Opteron, gcc 3.x
        CPU_OPT="-march=opteron"
        NGX_CPU_CACHE_LINE=64
    ;;

    sparc32)
        # build 32-bit UltraSparc binary
        CPU_OPT="-m32"
        CORE_LINK="$CORE_LINK -m32"
        NGX_CPU_CACHE_LINE=64
    ;;

    sparc64)
        # build 64-bit UltraSparc binary
        CPU_OPT="-m64"
        CORE_LINK="$CORE_LINK -m64"
        NGX_CPU_CACHE_LINE=64
    ;;

    ppc64)
        # build 64-bit PowerPC binary
        CPU_OPT="-m64"
        CPU_OPT="$CPU_OPT -falign-functions=32 -falign-labels=32"
        CPU_OPT="$CPU_OPT -falign-loops=32 -falign-jumps=32"
        CORE_LINK="$CORE_LINK -m64"
        NGX_CPU_CACHE_LINE=128
    ;;

esac

CC_AUX_FLAGS="$CC_AUX_FLAGS $CPU_OPT"

case "$NGX_GCC_VER" in
    2.7*)
        # batch build
        CPU_OPT=
    ;;
esac


CFLAGS="$CFLAGS $PIPE $CPU_OPT"

if [ ".$PCRE_OPT" = "." ]; then
    PCRE_OPT="-O2 -fomit-frame-pointer $PIPE $CPU_OPT"
else
    PCRE_OPT="$PCRE_OPT $PIPE"
fi

if [ ".$ZLIB_OPT" = "." ]; then
    ZLIB_OPT="-O2 -fomit-frame-pointer $PIPE $CPU_OPT"
else
    ZLIB_OPT="$ZLIB_OPT $PIPE"
fi


# warnings

# -W requires at least -O
CFLAGS="$CFLAGS ${NGX_GCC_OPT:--O} -W"

CFLAGS="$CFLAGS -Wall -Wpointer-arith"
#CFLAGS="$CFLAGS -Wconversion"
#CFLAGS="$CFLAGS -Winline"
#CFLAGS="$CFLAGS -Wmissing-prototypes"

case "$NGX_GCC_VER" in
    2.*)
        # we have a lot of the unused function arguments
        CFLAGS="$CFLAGS -Wno-unused"
    ;;

    *)
        # we have a lot of the unused function arguments
        CFLAGS="$CFLAGS -Wno-unused-parameter"
        # 4.2.1 shows the warning in wrong places
        #CFLAGS="$CFLAGS -Wunreachable-code"

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


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

# debug
CFLAGS="$CFLAGS -g"

# DragonFly's gcc3 generates DWARF
#CFLAGS="$CFLAGS -g -gstabs"

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