Mercurial > hg > nginx-quic
view auto/cc/ccc @ 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 | d620f497c50f |
children |
line wrap: on
line source
# Copyright (C) Igor Sysoev # Copyright (C) Nginx, Inc. # Compaq C V6.5-207 ngx_include_opt="-I" # warnings CFLAGS="$CFLAGS -msg_enable level6 -msg_fatal level6" CFLAGS="$CFLAGS -msg_disable unknownmacro" CFLAGS="$CFLAGS -msg_disable unusedincl" CFLAGS="$CFLAGS -msg_disable unnecincl" CFLAGS="$CFLAGS -msg_disable nestincl" CFLAGS="$CFLAGS -msg_disable strctpadding" CFLAGS="$CFLAGS -msg_disable ansialiascast" CFLAGS="$CFLAGS -msg_disable inlinestoclsmod" CFLAGS="$CFLAGS -msg_disable cxxkeyword" CFLAGS="$CFLAGS -msg_disable longlongsufx" CFLAGS="$CFLAGS -msg_disable valuepres" # STUB CFLAGS="$CFLAGS -msg_disable truncintcast" CFLAGS="$CFLAGS -msg_disable trunclongcast" CFLAGS="$CFLAGS -msg_disable truncintasn" CFLAGS="$CFLAGS -msg_disable trunclongint" CFLAGS="$CFLAGS -msg_disable intconcastsgn" CFLAGS="$CFLAGS -msg_disable intconstsign" CFLAGS="$CFLAGS -msg_disable switchlong" CFLAGS="$CFLAGS -msg_disable subscrbounds2" CFLAGS="$CFLAGS -msg_disable hexoctunsign" CFLAGS="$CFLAGS -msg_disable ignorecallval" CFLAGS="$CFLAGS -msg_disable nonstandcast" CFLAGS="$CFLAGS -msg_disable embedcomment" CFLAGS="$CFLAGS -msg_disable unreachcode" CFLAGS="$CFLAGS -msg_disable questcompare2" CFLAGS="$CFLAGS -msg_disable unusedtop" CFLAGS="$CFLAGS -msg_disable unrefdecl" CFLAGS="$CFLAGS -msg_disable bitnotint"