Mercurial > hg > nginx-quic
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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 | 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