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view docs/xml/ngx_core_module.xml @ 4113:a28ba1cdec27
Buffers reuse in chunked filter.
There were 2 buffers allocated on each buffer chain sent through chunked
filter (one buffer for chunk size, another one for trailing CRLF, about
120 bytes in total on 32-bit platforms). This resulted in large memory
consumption with long-lived requests sending many buffer chains. Usual
example of problematic scenario is streaming though proxy with
proxy_buffering set to off.
Introduced buffers reuse reduces memory consumption in the above problematic
scenario.
See here for initial report:
http://mailman.nginx.org/pipermail/nginx/2010-April/019814.html
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 15 Sep 2011 15:25:42 +0000 |
parents | 5e2103cffd80 |
children | a18b10aea510 |
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<?xml version="1.0"?> <!DOCTYPE module SYSTEM "../dtd/module.dtd"> <module name="Core Module" id="core_module"> <section id="example" name="Example Configuration"> <para> <example> user www www; worker_processes 2; error_log /var/log/nginx-error.log info; events { use kqueue; worker_connections 2048; } ... </example> </para> </section> <section id="directives" name="Directives"> <directive name="daemon"> <syntax>daemon <value>on</value> | <value>off</value></syntax> <default>daemon on</default> <context>main</context> <para> Determines whether nginx should become a daemon. Mainly used during development. </para> </directive> <directive name="env"> <syntax>env <argument>VAR</argument>[=<argument>VALUE</argument>]</syntax> <default>env TZ</default> <context>main</context> <para> Allows to limit a set of environment variables, change their values, or create new environment variables, for the following cases: <list type="bullet"> <listitem> variable inheritance during a <link doc="control.xml" id="upgrade">live upgrade</link> of an executable file; </listitem> <listitem> use of variables by the module <link doc="http/ngx_http_perl_module.xml">ngx_http_perl_module</link>; </listitem> <listitem> use of variables by worker processes. Please bear in mind that controlling system libraries in this way is not always possible as it is not uncommon for libraries to check variables only during initialization, well before they can be set using this directive. An exception from this is an above mentioned <link doc="control.xml" id="upgrade">live upgrade</link> of an executable file. </listitem> </list> </para> <para> The TZ variable is always inherited and made available to the module <link doc="http/ngx_http_perl_module.xml">ngx_http_perl_module</link>, unless configured explicitly. </para> <para> Usage example: <example> env MALLOC_OPTIONS; env PERL5LIB=/data/site/modules; env OPENSSL_ALLOW_PROXY_CERTS=1; </example> </para> </directive> <directive name="include"> <syntax>include <argument>file</argument> | <argument>mask</argument></syntax> <default/> <context/> <para> Includes another <argument>file</argument>, or files matching the specified <argument>mask</argument>, into configuration. Included files should consist of syntactically correct directives and blocks. </para> <para> Usage example: <example> include mime.types; include vhosts/*.conf; </example> </para> </directive> <directive name="master_process"> <syntax>master_process <value>on</value> | <value>off</value></syntax> <default>master_process on</default> <context>main</context> <para> Determines whether worker processes are started. This directive is intended for nginx developers. </para> </directive> <directive name="pid"> <syntax>pid <argument>file</argument></syntax> <default>pid nginx.pid</default> <context>main</context> <para> Defines a <argument>file</argument> which will store the process ID of the main process. </para> </directive> <directive name="ssl_engine"> <syntax>ssl_engine <argument>device</argument></syntax> <default/> <context>main</context> <para> Defines the name of the hardware SSL accelerator. </para> </directive> <directive name="user"> <syntax>user <argument>user</argument> [<argument>group</argument>]</syntax> <default>user nobody nobody</default> <context>main</context> <para> Defines <argument>user</argument> and <argument>group</argument> credentials used by worker processes. If <argument>group</argument> is omitted, a group whose name equals that of <argument>user</argument> is used. </para> </directive> <directive name="timer_resolution"> <syntax>timer_resolution <argument>interval</argument></syntax> <default/> <context>main</context> <para> Reduces timer resolution in worker processes, thus reducing the number of <c-func>gettimeofday</c-func> system calls made. By default, <c-func>gettimeofday</c-func> is called each time on receiving a kernel event. With reduced resolution, <c-func>gettimeofday</c-func> is only called once per specified <argument>interval</argument>. </para> <para> Example: <example> timer_resolution 100ms; </example> </para> <para> An internal implementation of interval depends on the method used: <list type="bullet"> <listitem> an <c-def>EVFILT_TIMER</c-def> filter if <value>kqueue</value> is used; </listitem> <listitem> <c-func>timer_create</c-func> if <value>eventport</value> is used; </listitem> <listitem> <c-func>setitimer</c-func> otherwise. </listitem> </list> </para> </directive> <directive name="worker_rlimit_core"> <syntax>worker_rlimit_core <argument>size</argument></syntax> <default/> <context>main</context> <para> Changes the limit on the largest size of a core file (<c-def>RLIMIT_CORE</c-def>) for worker processes. Used to increase the limit without restarting the main process. </para> </directive> <directive name="worker_rlimit_nofile"> <syntax>worker_rlimit_nofile <argument>number</argument></syntax> <default/> <context>main</context> <para> Changes the limit on the maximum number of open files (<c-def>RLIMIT_NOFILE</c-def>) for worker processes. Used to increase the limit without restarting the main process. </para> </directive> <directive name="worker_priority"> <syntax>worker_priority <argument>number</argument></syntax> <default>worker_priority 0</default> <context>main</context> <para> Defines a scheduling priority for worker processes like is done by the <command>nice</command>: a negative <argument>number</argument> means higher priority. Allowed range normally varies from -20 to 20. </para> <para> Example: <example> worker_priority -10; </example> </para> </directive> <directive name="worker_processes"> <syntax>worker_processes <argument>number</argument></syntax> <default>worker_processes 1</default> <context>main</context> <para> Defines the number of worker processes. </para> </directive> <directive name="working_directory"> <syntax>working_directory <argument>directory</argument></syntax> <default/> <context>main</context> <para> Defines a current working directory for a worker process. It is primarily used when writing a core-file, in which case a working process should have write permission for the specified directory. </para> </directive> </section> </module>