<!-- 
RSS generated by JIRA (9.7.1#970001-sha1:2222b88b221c4928ef0de3161136cc90c8356a66) at Thu Feb 08 07:42:43 UTC 2024

It is possible to restrict the fields that are returned in this document by specifying the 'field' parameter in your request.
For example, to request only the issue key and summary append 'field=key&field=summary' to the URL of your request.
-->
<rss version="0.92" >
<channel>
    <title>MongoDB Jira</title>
    <link>https://jira.mongodb.org</link>
    <description>This file is an XML representation of an issue</description>
    <language>en-us</language>    <build-info>
        <version>9.7.1</version>
        <build-number>970001</build-number>
        <build-date>13-04-2023</build-date>
    </build-info>


<item>
            <title>[DOCS-2131] Improve Linux transparent hugepages details in production notes</title>
                <link>https://jira.mongodb.org/browse/DOCS-2131</link>
                <project id="10380" key="DOCS">Documentation</project>
                    <description>&lt;p&gt;The &lt;a href=&quot;http://docs.mongodb.org/manual/administration/production-notes/#recommended-configuration&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;Linux Recommended Configuration section of the MongoDB production notes&lt;/a&gt; states&lt;/p&gt;

&lt;blockquote&gt;
&lt;p&gt;Do not use hugepages virtual memory pages as MongoDB performs better with normal virtual memory pages.&lt;/p&gt;&lt;/blockquote&gt;

&lt;p&gt;There are a few issues with this.&lt;/p&gt;

&lt;ol&gt;
	&lt;li&gt;It conflates &quot;hugepages&quot; and &quot;transparent hugepages&quot; (THP), which are related but not the same thing.
	&lt;ol&gt;
		&lt;li&gt;Hugepages must be preallocated and require application-level support (which MongoDB does not have).&lt;/li&gt;
		&lt;li&gt;Transparent hugepages (THP) are an operating system feature to automatically and transparently (to the application) use hugepages when possible.&lt;/li&gt;
	&lt;/ol&gt;
	&lt;/li&gt;
	&lt;li&gt;No information is given as to how users can:
	&lt;ol&gt;
		&lt;li&gt;Which Linux distributions (and versions) have THP enabled by default.&lt;/li&gt;
		&lt;li&gt;How users can check whether or not THP is enabled.&lt;/li&gt;
		&lt;li&gt;How users can investigate potential performance problems arising from THP.&lt;/li&gt;
		&lt;li&gt;How users can disable THP (temporarily and/or permanently).&lt;/li&gt;
	&lt;/ol&gt;
	&lt;/li&gt;
&lt;/ol&gt;


&lt;p&gt;Regarding the first point, it would be sufficient to adjust the sentence to read &quot;Ensure that transparent hugepages are disabled, as MongoDB performs better with normal virtual memory pages&quot; or some-such.&lt;/p&gt;

&lt;p&gt;I believe that THP is only enabled by default in RHEL6 and SLES11 (and derivatives), and is disabled otherwise, but this might not be the case.  If it is, this issue&apos;s relevance can be expected to increase over time as existing RHEL5 based systems are progressively upgraded to RHEL6.&lt;/p&gt;

&lt;p&gt;To check if THP is enabled, users need to check the contents of &lt;tt&gt;/sys/kernel/mm/transparent_hugepage/enabled&lt;/tt&gt; or &lt;tt&gt;/sys/kernel/mm/redhat_transparent_hugepage/enabled&lt;/tt&gt; on Redhat-derived systems (ie. RHEL, CentOS, Amazon, etc).  Some systems may have &lt;tt&gt;/sys/kernel/mm/transparent_hugepage&lt;/tt&gt; as a symlink to &lt;tt&gt;/sys/kernel/mm/redhat_transparent_hugepage&lt;/tt&gt;.  Users could potentially be instructed to run&lt;/p&gt;

&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;cat /sys/kernel/mm/*transparent_hugepage/enabled&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;

&lt;p&gt;to determine this in a Linux distro agnostic way.  If neither of these files are present, then THP support is not compiled into the Linux kernel, and so is as good as disabled.&lt;/p&gt;

&lt;p&gt;If THP is enabled, the output will look like:&lt;/p&gt;
&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;[always] never&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;
&lt;p&gt;or on some systems:&lt;/p&gt;
&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;[always] madvise never&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;

&lt;p&gt;If THP is disabled, the output will look like one of:&lt;/p&gt;
&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;always [never]&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;
&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;always madvise [never]&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;
&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;always [madvise] never&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;

&lt;p&gt;To check possible performance problems arising from THP, users can check the &lt;tt&gt;khugepaged&lt;/tt&gt; kernel thread process, as well as the contents of the other files in &lt;tt&gt;/sys/kernel/mm/*transparent_hugepage&lt;/tt&gt;.  In particular, any of the following are red flags:&lt;/p&gt;

&lt;ul&gt;
	&lt;li&gt;&lt;tt&gt;enabled&lt;/tt&gt; set to &lt;tt&gt;always&lt;/tt&gt;&lt;/li&gt;
	&lt;li&gt;&lt;tt&gt;defrag&lt;/tt&gt; set to &lt;tt&gt;always&lt;/tt&gt;&lt;/li&gt;
	&lt;li&gt;&lt;tt&gt;khugepaged/defrag&lt;/tt&gt; set to &lt;tt&gt;yes&lt;/tt&gt; or &lt;tt&gt;1&lt;/tt&gt;&lt;/li&gt;
	&lt;li&gt;High values in any of &lt;tt&gt;khugepaged/full_scans&lt;/tt&gt;, &lt;tt&gt;khugepaged/pages_collapsed&lt;/tt&gt; or &lt;tt&gt;khugepaged/pages_to_scan&lt;/tt&gt;&lt;/li&gt;
	&lt;li&gt;High cumulative cpu time for the &lt;tt&gt;khugepaged&lt;/tt&gt; process&lt;/li&gt;
	&lt;li&gt;High cpu% for the &lt;tt&gt;khugepaged&lt;/tt&gt; process&lt;/li&gt;
	&lt;li&gt;High or increasing value of &lt;tt&gt;AnonHugePages&lt;/tt&gt; in &lt;tt&gt;/proc/meminfo&lt;/tt&gt;&lt;/li&gt;
	&lt;li&gt;High or increasing value of &lt;tt&gt;thp_fault_alloc&lt;/tt&gt; (or any other &lt;tt&gt;thp_*&lt;/tt&gt; value) in &lt;tt&gt;/proc/vmstat&lt;/tt&gt;&lt;/li&gt;
&lt;/ul&gt;


&lt;p&gt;To disable THP temporarily (eg. to assess any possible impact), users can run as root:&lt;/p&gt;

&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;for i in /sys/kernel/mm/*transparent_hugepage/enabled; do echo never &amp;gt; $i; done&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;

&lt;p&gt;or equivalently as a regular user:&lt;/p&gt;

&lt;p/&gt;
&lt;div id=&quot;syntaxplugin&quot; class=&quot;syntaxplugin&quot; style=&quot;border: 1px dashed #bbb; border-radius: 5px !important; overflow: auto; max-height: 30em;&quot;&gt;
&lt;table cellspacing=&quot;0&quot; cellpadding=&quot;0&quot; border=&quot;0&quot; width=&quot;100%&quot; style=&quot;font-size: 1em; line-height: 1.4em !important; font-weight: normal; font-style: normal; color: black;&quot;&gt;
		&lt;tbody &gt;
				&lt;tr id=&quot;syntaxplugin_code_and_gutter&quot;&gt;
						&lt;td  style=&quot; line-height: 1.4em !important; padding: 0em; vertical-align: top;&quot;&gt;
					&lt;pre style=&quot;font-size: 1em; margin: 0 10px;  margin-top: 10px;   margin-bottom: 10px;  width: auto; padding: 0;&quot;&gt;&lt;span style=&quot;color: black; font-family: &apos;Consolas&apos;, &apos;Bitstream Vera Sans Mono&apos;, &apos;Courier New&apos;, Courier, monospace !important;&quot;&gt;echo never | sudo tee /sys/kernel/mm/*transparent_hugepage/enabled&lt;/span&gt;&lt;/pre&gt;
			&lt;/td&gt;
		&lt;/tr&gt;
			&lt;/tbody&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;p/&gt;

&lt;p&gt;This will stop &lt;tt&gt;khugepaged&lt;/tt&gt; from performing any actions.  Restarting &lt;tt&gt;mongod&lt;/tt&gt; is &lt;b&gt;not&lt;/b&gt; required for the new THP settings to take effect.&lt;/p&gt;

&lt;p&gt;When disabling THP, any previously allocated transparent hugepages (reported by &lt;tt&gt;AnonHugePages&lt;/tt&gt; in &lt;tt&gt;/proc/meminfo&lt;/tt&gt;) will not be broken up.  In most situations, this is unlikely to be a problem, but if it is suspected, they can be cleared by rebooting the host (and then immediately disabling THP again, or by disabling THP permanently, as below, prior to rebooting).&lt;/p&gt;

&lt;p&gt;To ensure THP is permanently disabled, users can either:&lt;/p&gt;

&lt;ul&gt;
	&lt;li&gt;put the above (root) command into their startup boot scripts (eg. &lt;tt&gt;/etc/rc.local&lt;/tt&gt;), or&lt;/li&gt;
	&lt;li&gt;add &lt;tt&gt;transparent_hugepage=never&lt;/tt&gt; to their Linux kernel commandline (eg. by editing the &lt;tt&gt;grub.conf&lt;/tt&gt; file if they are using the GRUB bootloader), and then reboot.  Note that some older Linux distributions have a bug where this setting is not effective, which means the above &lt;tt&gt;/etc/rc.local&lt;/tt&gt; solution must be used instead (and the safest option may be to simply do both).&lt;/li&gt;
&lt;/ul&gt;
</description>
                <environment></environment>
        <key id="95193">DOCS-2131</key>
            <summary>Improve Linux transparent hugepages details in production notes</summary>
                <type id="3" iconUrl="https://jira.mongodb.org/secure/viewavatar?size=xsmall&amp;avatarId=14718&amp;avatarType=issuetype">Task</type>
                                            <priority id="2" iconUrl="https://jira.mongodb.org/images/icons/priorities/critical.svg">Critical - P2</priority>
                        <status id="6" iconUrl="https://jira.mongodb.org/images/icons/statuses/closed.png" description="The issue is considered finished, the resolution is correct. Issues which are closed can be reopened.">Closed</status>
                    <statusCategory id="3" key="done" colorName="success"/>
                                    <resolution id="9">Done</resolution>
                                        <assignee username="michael.paik">Michael Paik</assignee>
                                    <reporter username="kevin.pulo@mongodb.com">Kevin Pulo</reporter>
                        <labels>
                    </labels>
                <created>Tue, 22 Oct 2013 05:35:43 +0000</created>
                <updated>Mon, 30 Oct 2023 19:38:51 +0000</updated>
                            <resolved>Fri, 3 Apr 2015 22:43:33 +0000</resolved>
                                                    <fixVersion>Server_Docs_20231030</fixVersion>
                                    <component>manual</component>
                        <due></due>
                            <votes>2</votes>
                                    <watches>11</watches>
                                                                                                                <comments>
                            <comment id="1338507" author="emily.hall" created="Wed, 27 Jul 2016 19:10:38 +0000"  >&lt;p&gt;Closed for housekeeping on 7/27/2016 by Emily Hall. &lt;br/&gt;
If you require additional support, please open a new ticket for prioritization. &lt;br/&gt;
Thanks,&lt;br/&gt;
Emily&lt;/p&gt;</comment>
                            <comment id="859751" author="xgen-internal-githook" created="Fri, 20 Mar 2015 21:15:24 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{u&apos;username&apos;: u&apos;mpaik&apos;, u&apos;name&apos;: u&apos;Michael Paik&apos;, u&apos;email&apos;: u&apos;michael.paik@10gen.com&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-2131&quot; title=&quot;Improve Linux transparent hugepages details in production notes&quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-2131&quot;&gt;&lt;del&gt;DOCS-2131&lt;/del&gt;&lt;/a&gt; Production Notes Edits&lt;br/&gt;
Branch: v2.6&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/docs/commit/f290feafbd8c239fc406b6fa40a5089684f4f726&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/docs/commit/f290feafbd8c239fc406b6fa40a5089684f4f726&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="859750" author="xgen-internal-githook" created="Fri, 20 Mar 2015 21:15:23 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{u&apos;username&apos;: u&apos;mpaik&apos;, u&apos;name&apos;: u&apos;Michael Paik&apos;, u&apos;email&apos;: u&apos;michael.paik@10gen.com&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-2131&quot; title=&quot;Improve Linux transparent hugepages details in production notes&quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-2131&quot;&gt;&lt;del&gt;DOCS-2131&lt;/del&gt;&lt;/a&gt;&lt;br/&gt;
Branch: v2.6&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/docs/commit/00640f419e12bc3706f39f259edb8126df420daa&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/docs/commit/00640f419e12bc3706f39f259edb8126df420daa&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="857337" author="xgen-internal-githook" created="Wed, 18 Mar 2015 21:27:11 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{u&apos;username&apos;: u&apos;mpaik&apos;, u&apos;name&apos;: u&apos;Michael Paik&apos;, u&apos;email&apos;: u&apos;michael.paik@10gen.com&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-2131&quot; title=&quot;Improve Linux transparent hugepages details in production notes&quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-2131&quot;&gt;&lt;del&gt;DOCS-2131&lt;/del&gt;&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-2131&quot; title=&quot;Improve Linux transparent hugepages details in production notes&quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-2131&quot;&gt;&lt;del&gt;DOCS-2131&lt;/del&gt;&lt;/a&gt; ProdNotes Edits&lt;br/&gt;
Branch: master&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/docs/commit/c338cfe66491061252dc0dc1b042a918a7aa3c93&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/docs/commit/c338cfe66491061252dc0dc1b042a918a7aa3c93&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="857336" author="xgen-internal-githook" created="Wed, 18 Mar 2015 21:27:10 +0000"  >&lt;p&gt;Author:&lt;/p&gt;
{u&apos;username&apos;: u&apos;mpaik&apos;, u&apos;name&apos;: u&apos;Michael Paik&apos;, u&apos;email&apos;: u&apos;michael.paik@10gen.com&apos;}
&lt;p&gt;Message: &lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-2131&quot; title=&quot;Improve Linux transparent hugepages details in production notes&quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-2131&quot;&gt;&lt;del&gt;DOCS-2131&lt;/del&gt;&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/browse/DOCS-2131&quot; title=&quot;Improve Linux transparent hugepages details in production notes&quot; class=&quot;issue-link&quot; data-issue-key=&quot;DOCS-2131&quot;&gt;&lt;del&gt;DOCS-2131&lt;/del&gt;&lt;/a&gt; ProdNotes Edits&lt;br/&gt;
Branch: master&lt;br/&gt;
&lt;a href=&quot;https://github.com/mongodb/docs/commit/c338cfe66491061252dc0dc1b042a918a7aa3c93&quot; class=&quot;external-link&quot; target=&quot;_blank&quot; rel=&quot;nofollow noopener&quot;&gt;https://github.com/mongodb/docs/commit/c338cfe66491061252dc0dc1b042a918a7aa3c93&lt;/a&gt;&lt;/p&gt;</comment>
                            <comment id="608956" author="kevin.pulo@10gen.com" created="Thu, 5 Jun 2014 01:50:23 +0000"  >&lt;p&gt;This comment expands on the rationale behind disabling THP when running MongoDB.&lt;/p&gt;

&lt;p&gt;For background, the main design goals of THP are:&lt;/p&gt;
&lt;ul&gt;
	&lt;li&gt;Easy to use&lt;/li&gt;
	&lt;li&gt;Reduce rate of TLB misses&lt;/li&gt;
	&lt;li&gt;Make TLB misses cheaper&lt;/li&gt;
&lt;/ul&gt;


&lt;p&gt;The main problems with THP (in a MongoDB setting) are:&lt;/p&gt;
&lt;ul&gt;
	&lt;li&gt;In the presence of memory pressure (very common with MongoDB), transparent hugepages can be automatically split so they are eligible to be swapped out (even though they won&apos;t be).  In extreme cases, pages can be repeatedly split and coalesced many times, wasting large amounts of CPU time.&lt;/li&gt;
	&lt;li&gt;The potential win from TLB savings (when THP is enabled) is likely to be very small relative to the expenses incurred by page faults and/or network traffic, both of which are vastly more common with MongoDB.  By contrast, the potential penalty from the overheads of running with THP may be very high.&lt;/li&gt;
&lt;/ul&gt;
</comment>
                    </comments>
                <issuelinks>
                            <issuelinktype id="10011">
                    <name>Depends</name>
                                                                <inwardlinks description="is depended on by">
                                        <issuelink>
            <issuekey id="185834">DOCS-4864</issuekey>
        </issuelink>
                            </inwardlinks>
                                    </issuelinktype>
                            <issuelinktype id="10012">
                    <name>Related</name>
                                            <outwardlinks description="related to">
                                        <issuelink>
            <issuekey id="186693">SERVER-17418</issuekey>
        </issuelink>
            <issuelink>
            <issuekey id="59561">SERVER-7953</issuekey>
        </issuelink>
                            </outwardlinks>
                                                                <inwardlinks description="is related to">
                                        <issuelink>
            <issuekey id="201455">DOCS-5330</issuekey>
        </issuelink>
            <issuelink>
            <issuekey id="188473">SERVER-17522</issuekey>
        </issuelink>
                            </inwardlinks>
                                    </issuelinktype>
                    </issuelinks>
                <attachments>
                    </attachments>
                <subtasks>
                    </subtasks>
                <customfields>
                                                <customfield id="customfield_10050" key="com.atlassian.jira.toolkit:comments">
                        <customfieldname># Replies</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>6.0</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                    <customfield id="customfield_10855" key="com.atlassian.jira.plugin.system.customfieldtypes:float">
                        <customfieldname>Actual Time</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>4.0</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        <customfield id="customfield_10055" key="com.atlassian.jira.ext.charting:firstresponsedate">
                        <customfieldname>Date of 1st Reply</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>Wed, 5 Feb 2014 08:15:06 +0000</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_10052" key="com.atlassian.jira.toolkit:dayslastcommented">
                        <customfieldname>Days since reply</customfieldname>
                        <customfieldvalues>
                                        7 years, 29 weeks ago
    
                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_18254" key="com.onresolve.jira.groovy.groovyrunner:scripted-field">
                        <customfieldname>Dependencies</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue><![CDATA[]]></customfieldvalue>


                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_15850" key="com.atlassian.jira.plugins.jira-development-integration-plugin:devsummary">
                        <customfieldname>Development</customfieldname>
                        <customfieldvalues>
                            
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    <customfield id="customfield_10057" key="com.atlassian.jira.toolkit:lastusercommented">
                        <customfieldname>Last comment by Customer</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>true</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_10056" key="com.atlassian.jira.toolkit:lastupdaterorcommenter">
                        <customfieldname>Last commenter</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>emet.ozar@mongodb.com</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_11151" key="com.atlassian.jira.toolkit:LastCommentDate">
                        <customfieldname>Last public comment date</customfieldname>
                        <customfieldvalues>
                            7 years, 29 weeks ago
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                            <customfield id="customfield_10051" key="com.atlassian.jira.toolkit:participants">
                        <customfieldname>Participants</customfieldname>
                        <customfieldvalues>
                                        <customfieldvalue>emily.hall</customfieldvalue>
            <customfieldvalue>xgen-internal-githook</customfieldvalue>
            <customfieldvalue>kevin.pulo@mongodb.com</customfieldvalue>
            <customfieldvalue>michael.paik</customfieldvalue>
    
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                        <customfield id="customfield_14254" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>Product Rank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>1|hrrlp3:</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                <customfield id="customfield_12550" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>Rank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>2|hrn51z:</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_10558" key="com.pyxis.greenhopper.jira:gh-global-rank">
                        <customfieldname>Rank (Obsolete)</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>48759</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                    <customfield id="customfield_10557" key="com.pyxis.greenhopper.jira:gh-sprint">
                        <customfieldname>Sprint</customfieldname>
                        <customfieldvalues>
                                <customfieldvalue id="435">Docs Sprint 17 - Ending 4/3</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                    <customfield id="customfield_10053" key="com.atlassian.jira.ext.charting:timeinstatus">
                        <customfieldname>Time In Status</customfieldname>
                        <customfieldvalues>
                            
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            <customfield id="customfield_14350" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>serverRank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>1|hrud5b:</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                </customfields>
    </item>
</channel>
</rss>