<para> OFED Version 2</para>
</entry>
</row>
- <row>
- <entry>
- <para> mx</para>
- </entry>
- <entry>
- <para> Myrinet MX</para>
- </entry>
- </row>
- <row>
- <entry>
- <para> gm</para>
- </entry>
- <entry>
- <para> Myrinet GM-2</para>
- </entry>
- </row>
</tbody>
</tgroup>
</informaltable>
</tgroup>
</informaltable>
</section>
- <section remap="h3">
- <title><indexterm><primary>configuring</primary><secondary>MX LND</secondary></indexterm>MX LND</title>
- <para><literal>MXLND</literal> supports a number of load-time parameters using Linux's module parameter system. The following variables are available:</para>
- <informaltable frame="all">
- <tgroup cols="2">
- <colspec colname="c1" colwidth="50*"/>
- <colspec colname="c2" colwidth="50*"/>
- <thead>
- <row>
- <entry>
- <para><emphasis role="bold">Variable</emphasis></para>
- </entry>
- <entry>
- <para><emphasis role="bold">Description</emphasis></para>
- </entry>
- </row>
- </thead>
- <tbody>
- <row>
- <entry>
- <para> <literal>n_waitd</literal></para>
- </entry>
- <entry>
- <para>Number of completion daemons.</para>
- </entry>
- </row>
- <row>
- <entry>
- <para> <literal>max_peers</literal></para>
- </entry>
- <entry>
- <para>Maximum number of peers that may connect.</para>
- </entry>
- </row>
- <row>
- <entry>
- <para> <literal>cksum</literal></para>
- </entry>
- <entry>
- <para>Enables small message (below 4 KB) checksums if set to a non-zero value.</para>
- </entry>
- </row>
- <row>
- <entry>
- <para> <literal>ntx</literal></para>
- </entry>
- <entry>
- <para>Number of total tx message descriptors.</para>
- </entry>
- </row>
- <row>
- <entry>
- <para> <literal>credits</literal></para>
- </entry>
- <entry>
- <para>Number of concurrent sends to a single peer.</para>
- </entry>
- </row>
- <row>
- <entry>
- <para> <literal>board</literal></para>
- </entry>
- <entry>
- <para>Index value of the Myrinet board (NIC).</para>
- </entry>
- </row>
- <row>
- <entry>
- <para> <literal>ep_id</literal></para>
- </entry>
- <entry>
- <para>MX endpoint ID.</para>
- </entry>
- </row>
- <row>
- <entry>
- <para> <literal>polling</literal></para>
- </entry>
- <entry>
- <para>Use zero (0) to block (wait). A value greater than 0 will poll that many times before blocking.</para>
- </entry>
- </row>
- <row>
- <entry>
- <para> <literal>hosts</literal></para>
- </entry>
- <entry>
- <para>IP-to-hostname resolution file.</para>
- </entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
- <para>Of the described variables, only hosts is required. It must be the absolute path to the MXLND hosts file.</para>
- <para>For example:</para>
- <screen>options kmxlnd hosts=/etc/hosts.mxlnd</screen>
- <para>The file format for the hosts file is:</para>
- <screen>IP HOST BOARD EP_ID</screen>
- <para>The values must be space and/or tab separated where:</para>
- <para><literal>IP</literal> is a valid IPv4 address</para>
- <para><literal>HOST</literal> is the name returned by <literal>`hostname`</literal> on that machine</para>
- <para><literal>BOARD</literal> is the index of the Myricom NIC (0 for the first card, etc.)</para>
- <para><literal>EP_ID</literal> is the MX endpoint ID</para>
- <para>To obtain the optimal performance for your platform, you may want to vary the remaining options.</para>
- <para><literal>n_waitd(1)</literal> sets the number of threads that process completed MX requests (sends and receives).</para>
- <para><literal>max_peers(1024)</literal> tells MXLND the upper limit of machines that it will need to communicate with. This affects how many receives it will pre-post and each receive will use one page of memory. Ideally, on clients, this value will be equal to the total number of Lustre servers (MDS and OSS). On servers, it needs to equal the total number of machines in the storage system. cksum (0) turns on small message checksums. It can be used to aid in troubleshooting. MX also provides an optional checksumming feature which can check all messages (large and small). For details, see the MX README.</para>
- <para><literal>ntx(256)</literal> is the number of total sends in flight from this machine. In actuality, MXLND reserves half of them for connect messages so make this value twice as large as you want for the total number of sends in flight.</para>
- <para><literal>credits(8)</literal> is the number of in-flight messages for a specific peer.
- This is part of the flow-control system in provided by the Lustre software. Increasing this
- value may improve performance but it requires more memory because each message requires at
- least one page.</para>
- <para><literal>board(0)</literal> is the index of the Myricom NIC. Hosts can have multiple Myricom NICs and this identifies which one MXLND should use. This value must match the board value in your MXLND hosts file for this host.</para>
- <para><literal>ep_id(3)</literal> is the MX endpoint ID. Each process that uses MX is required to have at least one MX endpoint to access the MX library and NIC. The ID is a simple index starting at zero (0). This value must match the endpoint ID value in your MXLND hosts file for this host.</para>
- <para><literal>polling(0)</literal> determines whether this host will poll or block for MX request completions. A value of 0 blocks and any positive value will poll that many times before blocking. Since polling increases CPU usage, we suggest that you set this to zero (0) on the client and experiment with different values for servers.</para>
- </section>
</section>
</chapter>
git://git.whamcloud.com / doc / manual.git / blobdiff