diff mbox

[dpdk-dev,v2] doc: add use of mlockall to programmers guide

Message ID df891b598231a80e360ecd7af7b6f8847da7f151.1506938439.git.echaudro@redhat.com (mailing list archive)
State Accepted, archived
Delegated to: Ferruh Yigit
Headers

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK

Commit Message

Eelco Chaudron Oct. 2, 2017, 10:01 a.m. UTC 
  When I was adding mlockall() to the testpmd application it was
suggested to add a reference to the use case of mlockall(). This patch
adds is.

Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
---
 doc/guides/prog_guide/writing_efficient_code.rst | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

Comments

John McNamara Oct. 2, 2017, 10:11 a.m. UTC | #1 
> -----Original Message-----
> From: Eelco Chaudron [mailto:echaudro@redhat.com]
> Sent: Monday, October 2, 2017 11:02 AM
> To: Mcnamara, John <john.mcnamara@intel.com>
> Cc: dev@dpdk.org
> Subject: [PATCH v2] doc: add use of mlockall to programmers guide
> 
> When I was adding mlockall() to the testpmd application it was suggested
> to add a reference to the use case of mlockall(). This patch adds is.
> 
> Signed-off-by: Eelco Chaudron <echaudro@redhat.com>

Acked-by: John McNamara <john.mcnamara@intel.com>
Ferruh Yigit Oct. 9, 2017, 11:42 p.m. UTC | #2 
On 10/2/2017 11:11 AM, Mcnamara, John wrote:
> 
> 
>> -----Original Message-----
>> From: Eelco Chaudron [mailto:echaudro@redhat.com]
>> Sent: Monday, October 2, 2017 11:02 AM
>> To: Mcnamara, John <john.mcnamara@intel.com>
>> Cc: dev@dpdk.org
>> Subject: [PATCH v2] doc: add use of mlockall to programmers guide
>>
>> When I was adding mlockall() to the testpmd application it was suggested
>> to add a reference to the use case of mlockall(). This patch adds is.
>>
>> Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
> 
> Acked-by: John McNamara <john.mcnamara@intel.com>

Applied to dpdk/master, thanks.
diff mbox

Patch

diff --git a/doc/guides/prog_guide/writing_efficient_code.rst b/doc/guides/prog_guide/writing_efficient_code.rst
index 8223aceea..d7ac6778b 100644
--- a/doc/guides/prog_guide/writing_efficient_code.rst
+++ b/doc/guides/prog_guide/writing_efficient_code.rst
@@ -105,6 +105,21 @@  meaning that if all memory access operations are done on the first channel only,
 
 By default, the  :ref:`Mempool Library <Mempool_Library>` spreads the addresses of objects among memory channels.
 
+Locking memory pages
+~~~~~~~~~~~~~~~~~~~~
+
+The underlying operating system is allowed to load/unload memory pages at its own discretion.
+These page loads could impact the performance, as the process is on hold when the kernel fetches them.
+
+To avoid these you could pre-load, and lock them into memory with the ``mlockall()`` call.
+
+.. code-block:: c
+
+    if (mlockall(MCL_CURRENT | MCL_FUTURE)) {
+        RTE_LOG(NOTICE, USER1, "mlockall() failed with error \"%s\"\n",
+                strerror(errno));
+    }
+
 Communication Between lcores
 ----------------------------