[spp] [PATCH 11/15] docs: add performance_opt section
ogawa.yasufumi at lab.ntt.co.jp
ogawa.yasufumi at lab.ntt.co.jp
Thu Feb 1 05:04:57 CET 2018
From: Yasufumi Ogawa <ogawa.yasufumi at lab.ntt.co.jp>
Add section for performance optimization containing following topics.
* Reduce context switches
* Optimizing QEMU performance
Signed-off-by: Yasufumi Ogawa <ogawa.yasufumi at lab.ntt.co.jp>
---
docs/guides/setup/index.rst | 1 +
docs/guides/setup/performance_opt.rst | 106 ++++++++++++++++++++++++++++++++++
2 files changed, 107 insertions(+)
create mode 100644 docs/guides/setup/performance_opt.rst
diff --git a/docs/guides/setup/index.rst b/docs/guides/setup/index.rst
index 972132d..0ac18af 100644
--- a/docs/guides/setup/index.rst
+++ b/docs/guides/setup/index.rst
@@ -38,3 +38,4 @@ Setup Guide
getting_started
howto_use
use_cases
+ performance_opt
diff --git a/docs/guides/setup/performance_opt.rst b/docs/guides/setup/performance_opt.rst
new file mode 100644
index 0000000..2bf8a5e
--- /dev/null
+++ b/docs/guides/setup/performance_opt.rst
@@ -0,0 +1,106 @@
+.. BSD LICENSE
+ Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in
+ the documentation and/or other materials provided with the
+ distribution.
+ * Neither the name of Intel Corporation nor the names of its
+ contributors may be used to endorse or promote products derived
+ from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+Performance Optimization
+========================
+
+Reduce Context Switches
+-----------------------
+
+Use the ``isolcpus`` Linux kernel parameter to isolate them
+from Linux scheduler to reduce context switches.
+It prevents workloads of other processes than DPDK running on
+reserved cores with ``isolcpus`` parameter.
+
+For Ubuntu 16.04, define ``isolcpus`` in ``/etc/default/grub``.
+
+.. code-block:: console
+
+ GRUB_CMDLINE_LINUX_DEFAULT=“isolcpus=0-3,5,7”
+
+The value of this ``isolcpus`` depends on your environment and usage.
+This example reserves six cores(0,1,2,3,5,7).
+
+
+Optimizing QEMU Performance
+---------------------------
+
+QEMU process runs threads for vcpu emulation. It is effective strategy
+for pinning vcpu threads to decicated cores.
+
+To find vcpu threads, you use ``ps`` command to find PID of QEMU process
+and ``pstree`` command for threads launched from QEMU process.
+
+.. code-block:: console
+
+ $ ps ea
+ PID TTY STAT TIME COMMAND
+ 192606 pts/11 Sl+ 4:42 ./x86_64-softmmu/qemu-system-x86_64 -cpu host ...
+
+Run ``pstree`` with ``-p`` and this PID to find all threads launched from QEMU.
+
+.. code-block:: console
+
+ $ pstree -p 192606
+ qemu-system-x86(192606)--+--{qemu-system-x8}(192607)
+ |--{qemu-system-x8}(192623)
+ |--{qemu-system-x8}(192624)
+ |--{qemu-system-x8}(192625)
+ |--{qemu-system-x8}(192626)
+
+Update affinity by using ``taskset`` command to pin vcpu threads.
+The vcpu threads is listed from the second entry and later.
+In this example, assign PID 192623 to core 4, PID 192624 to core 5
+and so on.
+
+.. code-block:: console
+
+ $ sudo taskset -pc 4 192623
+ pid 192623's current affinity list: 0-31
+ pid 192623's new affinity list: 4
+ $ sudo taskset -pc 5 192624
+ pid 192624's current affinity list: 0-31
+ pid 192624's new affinity list: 5
+ $ sudo taskset -pc 6 192625
+ pid 192625's current affinity list: 0-31
+ pid 192625's new affinity list: 6
+ $ sudo taskset -pc 7 192626
+ pid 192626's current affinity list: 0-31
+ pid 192626's new affinity list: 7
+
+
+Reference
+---------
+
+* [1] `Best pinning strategy for latency/performance trade-off <https://www.redhat.com/archives/vfio-users/2017-February/msg00010.html>`_
+* [2] `PVP reference benchmark setup using testpmd <http://dpdk.org/doc/guides/howto/pvp_reference_benchmark.html>`_
+* [3] `Enabling Additional Functionality <http://dpdk.org/doc/guides/linux_gsg/enable_func.html>`_
+* [4] `How to get best performance with NICs on Intel platforms <http://dpdk.org/doc/guides/linux_gsg/nic_perf_intel_platform.html>`_
--
2.7.4
More information about the spp
mailing list