nginx event module directive

accept_mutexSyntax: accept_mutex [ on | off ]Default: onnginx uses the connection mutex to perform sequential accept() system calls.
accept_mutex_ delaySyntax: accept_mutex_delay Nms;Default: 500msIf a process does not have a mutex lock, it will be delayed for at least how long. By default, the delay is 500ms.
debug_connectionSyntax: debug_connection [ip | CIDR]Default: noneThis command can specify the ip used to print debug logsFor example

<span>error_log</span> /var/log/nginx/errors;
<span>events</span><span>{</span><span>debug_connection</span><span>192.168</span><span>.1</span><span>.1</span>;

<span>}</span>

devpoll_changes devpoll_eventskqueue_eventsepoll_eventsSyntax: devpoll_changesThese parameters specify the number of events passed to or from the kernel in the specified way. The default devpoll value is 32, and the rest are 5 12.
multi_acceptSyntax: multi_accept [ on | off ]Default: offmulti_accept Specify after nginx gets a new connection , whether to call accept as many times as possible () Get connection rtsig_signoSyntax: rtsig_signo

Nginx uses two signals after rtsig mode is enabled. This instruction specifies the first signal number, and the second signal number is the first plus 1

The default value of rtsig_signo is SIGRTMIN+10 (40).

rtsig_overflow_eventsrtsig_overflow_testrtsig_overflow_thresholdSyntax: rtsig_overflow_*These three instructions are all related to processing the rtsig queue overflow. When the rtsig queue overflows, nginx clears the queue and switches between poll() and rtsig. Poll() will continuously process the unprocessed events. , at the same time, in order to prevent new overflows, rtsig will periodically reduce the queue elements. When the overflow is processed, it will switch back to rtsigrtsig_overflow_events specifies the number of poll listeners, the default is 16
rtsig_overflow_test After specifying how many events poll handles, rtsig reduces the queue elements. The default is 32
rtsig_overflow_thre shold This option is only valid in linux 2.4. The The option specifies how much of the queue is filled before reducing the queue elements. The default is 1/10.

useSyntax: use [ kqueue | rtsig | epoll | /dev/poll | select poll | | eventport ]Default: If more than one event model is specified when ./configure, you can set one of them to tell nginx which event model to use. By default, nginx will find the most suitable event model for the system during ./configure
. nginx’s event models are as follows
select - standard method. It is the compile-time default method if there is no more efficient method for the current platform. You can enable or disable this module using the configuration parameters --with-select_module and --without-select_module

. poll - the standard method. It is the compile-time default method if there is no more efficient method for the current platform. You can enable or disable this module using the configuration parameters --with-poll_module and

--without-poll_module

. kqueue - Efficient method, used in FreeBSD 4.1+, OpenBSD 2.9+, NetBSD 2.0 and MacOS X. Using kqueue on a dual-processor MacOS X system may cause a kernel panic. epoll - An efficient method, used in Linux kernel version 2.6 and later systems. In some distributions, such as SuSE 8.2, there is a patch to support epoll in the 2.4 kernel.

rtsig - executable real-time signal, used on systems with Linux kernel version 2.2.19 or later. By default, no more than 1024 POSIX real-time (queued) signals can appear in the entire system. This situation is inefficient for heavily loaded servers; so it is necessary to increase the queue size by adjusting the kernel parameter

/proc/sys/kernel/rtsig-max

. But starting from Linux kernel version 2.6.6-mm2, This parameter is no longer used, and there is a separate signal queue for each process. The size of this queue can be adjusted with the RLIMIT_SIGPENDING parameter. When this queue becomes too congested, nginx gives up on it and starts using the

poll

method to handle connections until it returns to normal. /dev/poll - Efficient method, used on Solaris 7 11/99+, HP/UX 11.22+ (eventport), IRIX 6.5.15+ and Tru64 UNIX 5.1A+. eventport - Efficient method, used on Solaris 10. In order to prevent kernel panic problems, it is necessary to install this security patch.

worker_connectionsSyntax: worker_connections numberMaximum number of connections per process The maximum number of concurrencies can be calculated through worker_connections and worker_proceses, that is, the maximum number of concurrencies = work_connections x work_process

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