[v7,10/10] doc: update programmer's guide for power library
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Message ID 1b4dd60949bbada468f9fe9fcdc3f5357aaa1ec8.1602763439.git.anatoly.burakov@intel.com
State Superseded, archived
Delegated to: Thomas Monjalon
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  • [v7,01/10] eal: add new x86 cpuid support for WAITPKG
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Commit Message

Burakov, Anatoly Oct. 15, 2020, 12:04 p.m. UTC
From: Liang Ma <liang.j.ma@intel.com>

Update programmer's guide to document PMD power management usage.

Signed-off-by: Liang Ma <liang.j.ma@intel.com>
Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: David Hunt <david.hunt@intel.com>

    - Moved l3fwd-power update to the l3fwd-power-related commit
    - Some rewordings and clarifications

 doc/guides/prog_guide/power_man.rst | 42 +++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

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diff --git a/doc/guides/prog_guide/power_man.rst b/doc/guides/prog_guide/power_man.rst
index 0a3755a901..38c64d31e4 100644
--- a/doc/guides/prog_guide/power_man.rst
+++ b/doc/guides/prog_guide/power_man.rst
@@ -192,6 +192,45 @@  User Cases
 The mechanism can applied to any device which is based on polling. e.g. NIC, FPGA.
+PMD Power Management API
+Existing power management mechanisms require developers to change application
+design or change code to make use of it. The PMD power management API provides a
+convenient alternative by utilizing Ethernet PMD RX callbacks, and triggering
+power saving whenever empty poll count reaches a certain number.
+   This power saving scheme will put the CPU into optimized power state and use
+   the UMWAIT/UMONITOR instructions to monitor the Ethernet PMD RX descriptor
+   address, and wake the CPU up whenever there's new traffic.
+  * Pause
+   This power saving scheme will use the `rte_pause` function to avoid busy
+   polling.
+  * Frequency scaling
+   This power saving scheme will use existing power library functionality to
+   scale the core frequency up/down depending on traffic volume.
+.. note::
+   Currently, this power management API is limited to mandatory mapping of 1
+   queue to 1 core (multiple queues are supported, but they must be polled from
+   different cores).
+API Overview for PMD Power Management
+* **Queue Enable**: Enable specific power scheme for certain queue/port/core
+* **Queue Disable**: Disable power scheme for certain queue/port/core
@@ -200,3 +239,6 @@  References
 *   The :doc:`../sample_app_ug/vm_power_management`
     chapter in the :doc:`../sample_app_ug/index` section.
+*   The :doc:`../sample_app_ug/rxtx_callbacks`
+    chapter in the :doc:`../sample_app_ug/index` section.