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samba-mirror/docs-xml/manpages/vfs_io_uring.8.xml
Stefan Metzmacher 195e88cea3 s3:modules: add vfs_io_uring module
The module makes use of the new io_uring infrastructure
(intruduced in linux 5.1), see https://lwn.net/Articles/778411/ and
http://git.kernel.dk/cgit/liburing/

Currently this only implements SMB_VFS_{PREAD,PWRITE,FSYNC}_SEND/RECV
and avoids the overhead of our userspace threadpool.

In future we'll hopefully make more use of more advanced io_uring
features.

For now we don't have automated tests as our test infrastructure
doesn't use a recent kernel. At least we're able to do compile tests
on fedora31.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>

Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Sat Feb 15 11:37:45 UTC 2020 on sn-devel-184
2020-02-15 11:37:45 +00:00

108 lines
2.7 KiB
XML

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE refentry PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
<refentry id="vfs_io_uring.8">
<refmeta>
<refentrytitle>vfs_io_uring</refentrytitle>
<manvolnum>8</manvolnum>
<refmiscinfo class="source">Samba</refmiscinfo>
<refmiscinfo class="manual">System Administration tools</refmiscinfo>
<refmiscinfo class="version">&doc.version;</refmiscinfo>
</refmeta>
<refnamediv>
<refname>vfs_io_uring</refname>
<refpurpose>Implement async io in Samba vfs using io_uring of Linux (>= 5.1).</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>vfs objects = io_uring</command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>DESCRIPTION</title>
<para>This VFS module is part of the
<citerefentry><refentrytitle>samba</refentrytitle>
<manvolnum>7</manvolnum></citerefentry> suite.</para>
<para>The <command>io_uring</command> VFS module enables asynchronous
pread, pwrite and fsync using the io_uring infrastructure of Linux (>= 5.1).
This provides much less overhead compared to the usage of the pthreadpool for
async io.</para>
<para>This module SHOULD be listed last in any module stack as
it requires real kernel file descriptors.</para>
</refsect1>
<refsect1>
<title>EXAMPLES</title>
<para>Straight forward use:</para>
<programlisting>
<smbconfsection name="[cooldata]"/>
<smbconfoption name="path">/data/ice</smbconfoption>
<smbconfoption name="vfs objects">io_uring</smbconfoption>
</programlisting>
</refsect1>
<refsect1>
<title>OPTIONS</title>
<variablelist>
<varlistentry>
<term>io_uring:num_entries = NUMBER_OF_QUEUE_ENTRIES</term>
<listitem>
<para>The number of entries in the submission queue.
The maximum allowed value depends on the kernel version
and the kernel will roundup the value to a power of 2.
</para>
<para>The default is '128'.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>io_uring:sqpoll = BOOL</term>
<listitem>
<para>Use the IORING_SETUP_SQPOLL feature.
</para>
<para>The default is 'no'.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>SEE ALSO</title>
<para>
<citerefentry><refentrytitle>io_uring_setup</refentrytitle><manvolnum>2</manvolnum></citerefentry>.
</para>
</refsect1>
<refsect1>
<title>VERSION</title>
<para>This man page is part of version &doc.version; of the Samba suite.
</para>
</refsect1>
<refsect1>
<title>AUTHOR</title>
<para>The original Samba software and related utilities
were created by Andrew Tridgell. Samba is now developed
by the Samba Team as an Open Source project similar
to the way the Linux kernel is developed.</para>
</refsect1>
</refentry>