From: Liang Ma <liang.j.ma@intel.com>
To: david.hunt@intel.com
Cc: dev@dpdk.org, lei.a.yao@intel.com, ktraynor@redhat.com,
marko.kovacevic@intel.com, Liang Ma <liang.j.ma@intel.com>
Subject: [dpdk-dev] [PATCH v9 3/4] doc/guides/pro_guide/power-man: update the power API
Date: Fri, 28 Sep 2018 15:58:33 +0100 [thread overview]
Message-ID: <1538146714-30973-3-git-send-email-liang.j.ma@intel.com> (raw)
In-Reply-To: <1538146714-30973-1-git-send-email-liang.j.ma@intel.com>
Update the document for empty poll API.
Change Logs:
v9: minor changes for syntax. Update document.
Signed-off-by: Liang Ma <liang.j.ma@intel.com>
---
doc/guides/prog_guide/power_man.rst | 86 +++++++++++++++++++++++++++++++++++++
1 file changed, 86 insertions(+)
diff --git a/doc/guides/prog_guide/power_man.rst b/doc/guides/prog_guide/power_man.rst
index eba1cc6..68b7e8b 100644
--- a/doc/guides/prog_guide/power_man.rst
+++ b/doc/guides/prog_guide/power_man.rst
@@ -106,6 +106,92 @@ User Cases
The power management mechanism is used to save power when performing L3 forwarding.
+
+Empty Poll API
+--------------
+
+Abstract
+~~~~~~~~
+
+For packet processing workloads such as DPDK polling is continuous.
+This means CPU cores always show 100% busy independent of how much work
+those cores are doing. It is critical to accurately determine how busy
+a core is hugely important for the following reasons:
+
+ * No indication of overload conditions
+ * User does not know how much real load is on a system, resulting
+ in wasted energy as no power management is utilized
+
+Compared to the original l3fwd-power design, instead of going to sleep
+after detecting an empty poll, the new mechanism just lowers the core frequency.
+As a result, the application does not stop polling the device, which leads
+to improved handling of bursts of traffic.
+
+When the system become busy, the empty poll mechanism can also increase the core
+frequency (including turbo) to do best effort for intensive traffic. This gives
+us more flexible and balanced traffic awareness over the standard l3fwd-power
+application.
+
+
+Proposed Solution
+~~~~~~~~~~~~~~~~~
+The proposed solution focuses on how many times empty polls are executed.
+The less the number of empty polls, means current core is busy with processing
+workload, therefore, the higher frequency is needed. The high empty poll number
+indicates the current core not doing any real work therefore, we can lower the
+frequency to safe power.
+
+In the current implementation, each core has 1 empty-poll counter which assume
+1 core is dedicated to 1 queue. This will need to be expanded in the future to
+support multiple queues per core.
+
+Power state definition:
+^^^^^^^^^^^^^^^^^^^^^^^
+
+* LOW: Not currently used, reserved for future use.
+
+* MED: the frequency is used to process modest traffic workload.
+
+* HIGH: the frequency is used to process busy traffic workload.
+
+There are two phases to establish the power management system:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+* Training phase. This phase is used to measure the optimal frequency
+ change thresholds for a given system. The thresholds will differ from
+ system to system due to differences in processor micro-architecture,
+ cache and device configurations.
+ In this phase, the user must ensure that no traffic can enter the
+ system so that counts can be measured for empty polls at low, medium
+ and high frequencies. Each frequency is measured for two seconds.
+ Once the training phase is complete, the threshold numbers are
+ displayed, and normal mode resumes, and traffic can be allowed into
+ the system. These threshold number can be used on the command line
+ when starting the application in normal mode to avoid re-training
+ every time.
+
+* Normal phase. Every 10ms the run-time counters are compared
+ to the supplied threshold values, and the decision will be made
+ whether to move to a different power state (by adjusting the
+ frequency).
+
+API Overview for Empty Poll Power Management
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+* **State Init**: initialize the power management system.
+
+* **State Free**: free the resource hold by power management system.
+
+* **Update Empty Poll Counter**: update the empty poll counter.
+
+* **Update Valid Poll Counter**: update the valid poll counter.
+
+* **Set the Fequence Index**: update the power state/frequency mapping.
+
+* **Detect empty poll state change**: empty poll state change detection algorithm then take action.
+
+User Cases
+----------
+The mechanism can applied to any device which is based on polling. e.g. NIC, FPGA.
+
References
----------
--
2.7.5
next prev parent reply other threads:[~2018-09-28 14:58 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-08 9:57 [dpdk-dev] [PATCH v1 1/2] lib/librte_power: traffic pattern aware power control Liang Ma
2018-06-08 9:57 ` [dpdk-dev] [PATCH v1 2/2] examples/l3fwd-power: simple app update to support new API Liang Ma
2018-06-19 10:31 ` Hunt, David
2018-06-08 15:26 ` [dpdk-dev] [PATCH v2 1/2] lib/librte_power: traffic pattern aware power control Liang Ma
2018-06-08 15:26 ` [dpdk-dev] [PATCH v2 2/2] examples/l3fwd-power: simple app update to support new API Liang Ma
2018-06-20 14:44 ` [dpdk-dev] [PATCH v3 1/2] lib/librte_power: traffic pattern aware power control Liang Ma
2018-06-20 14:44 ` [dpdk-dev] [PATCH v3 2/2] examples/l3fwd-power: simple app update to support new API Liang Ma
2018-06-26 11:40 ` [dpdk-dev] [PATCH v4 1/2] lib/librte_power: traffic pattern aware power control Radu Nicolau
2018-06-26 11:40 ` [dpdk-dev] [PATCH v4 2/2] examples/l3fwd-power: simple app update to support new API Radu Nicolau
2018-06-26 13:03 ` Hunt, David
2018-06-26 13:03 ` [dpdk-dev] [PATCH v4 1/2] lib/librte_power: traffic pattern aware power control Hunt, David
2018-06-27 17:33 ` Kevin Traynor
2018-07-05 14:45 ` Liang, Ma
2018-07-12 17:30 ` Thomas Monjalon
2018-09-11 9:19 ` Hunt, David
2018-09-13 9:46 ` Kevin Traynor
2018-09-13 13:30 ` Liang, Ma
2018-07-10 16:04 ` [dpdk-dev] [PATCH v5 " Radu Nicolau
2018-07-10 16:04 ` [dpdk-dev] [PATCH v5 2/2] examples/l3fwd-power: simple app update to support new API Radu Nicolau
2018-08-31 15:04 ` [dpdk-dev] [PATCH v6 1/4] lib/librte_power: traffic pattern aware power control Liang Ma
2018-08-31 15:04 ` [dpdk-dev] [PATCH v6 2/4] examples/l3fwd-power: simple app update for new API Liang Ma
2018-08-31 15:04 ` [dpdk-dev] [PATCH v6 3/4] doc/guides/proguides/power-man: update the power API Liang Ma
2018-08-31 15:04 ` [dpdk-dev] [PATCH v6 4/4] doc/guides/sample_app_ug/l3_forward_power_man.rst: empty poll update Liang Ma
2018-09-04 1:11 ` [dpdk-dev] [PATCH v6 1/4] lib/librte_power: traffic pattern aware power control Yao, Lei A
2018-09-04 2:09 ` Yao, Lei A
2018-09-04 14:10 ` [dpdk-dev] [PATCH v7 " Liang Ma
2018-09-04 14:10 ` [dpdk-dev] [PATCH v7 2/4] examples/l3fwd-power: simple app update for new API Liang Ma
2018-09-04 14:10 ` [dpdk-dev] [PATCH v7 3/4] doc/guides/proguides/power-man: update the power API Liang Ma
2018-09-04 14:10 ` [dpdk-dev] [PATCH v7 4/4] doc/guides/sample_app_ug/l3_forward_power_man.rst: empty poll update Liang Ma
2018-09-13 10:54 ` [dpdk-dev] [PATCH v7 1/4] lib/librte_power: traffic pattern aware power control Kevin Traynor
2018-09-13 13:37 ` Liang, Ma
2018-09-13 14:05 ` Hunt, David
2018-09-17 13:30 ` [dpdk-dev] [PATCH v8 " Liang Ma
2018-09-17 13:30 ` [dpdk-dev] [PATCH v8 2/4] examples/l3fwd-power: simple app update for new API Liang Ma
2018-09-28 11:19 ` Hunt, David
2018-10-02 10:18 ` Liang, Ma
2018-09-17 13:30 ` [dpdk-dev] [PATCH v8 3/4] doc/guides/proguide/power-man: update the power API Liang Ma
2018-09-25 12:31 ` Kovacevic, Marko
2018-09-25 12:44 ` Kovacevic, Marko
2018-09-28 12:30 ` Hunt, David
2018-09-17 13:30 ` [dpdk-dev] [PATCH v8 4/4] doc/guides/sample_app_ug/l3_forward_power_man.rst: empty poll update Liang Ma
2018-09-25 13:20 ` Kovacevic, Marko
2018-09-28 12:43 ` Hunt, David
2018-09-28 12:52 ` Liang, Ma
2018-09-28 10:47 ` [dpdk-dev] [PATCH v8 1/4] lib/librte_power: traffic pattern aware power control Hunt, David
2018-10-02 10:13 ` Liang, Ma
2018-09-28 14:58 ` [dpdk-dev] [PATCH v9 " Liang Ma
2018-09-28 14:58 ` [dpdk-dev] [PATCH v9 2/4] examples/l3fwd-power: simple app update for new API Liang Ma
2018-09-28 14:58 ` Liang Ma [this message]
2018-10-02 13:48 ` [dpdk-dev] [PATCH v10 1/4] lib/librte_power: traffic pattern aware power control Liang Ma
2018-10-02 13:48 ` [dpdk-dev] [PATCH v10 2/4] examples/l3fwd-power: simple app update for new API Liang Ma
2018-10-02 14:23 ` Hunt, David
2018-10-02 13:48 ` [dpdk-dev] [PATCH v10 3/4] doc/guides/pro_guide/power-man: update the power API Liang Ma
2018-10-02 14:24 ` Hunt, David
2018-10-02 13:48 ` [dpdk-dev] [PATCH v10 4/4] doc/guides/sample_app_ug/l3_forward_power_man.rst: update Liang Ma
2018-10-02 14:25 ` Hunt, David
2018-10-02 14:22 ` [dpdk-dev] [PATCH v10 1/4] lib/librte_power: traffic pattern aware power control Hunt, David
2018-10-12 1:59 ` Yao, Lei A
2018-10-12 10:02 ` Liang, Ma
2018-10-12 13:22 ` Yao, Lei A
2018-10-19 10:23 ` [dpdk-dev] [PATCH v11 1/5] " Liang Ma
2018-10-19 10:23 ` [dpdk-dev] [PATCH v11 2/5] examples/l3fwd-power: simple app update for new API Liang Ma
2018-10-19 10:23 ` [dpdk-dev] [PATCH v11 3/5] doc/guides/pro_guide/power-man: update the power API Liang Ma
2018-10-19 10:23 ` [dpdk-dev] [PATCH v11 5/5] doc: update release notes for empty poll library Liang Ma
2018-10-19 11:07 ` [dpdk-dev] [PATCH v12 1/5] lib/librte_power: traffic pattern aware power control Liang Ma
2018-10-19 11:07 ` [dpdk-dev] [PATCH v12 2/5] examples/l3fwd-power: simple app update for new API Liang Ma
2018-10-19 11:07 ` [dpdk-dev] [PATCH v12 3/5] doc/guides/pro_guide/power-man: update the power API Liang Ma
2018-10-19 11:07 ` [dpdk-dev] [PATCH v12 4/5] doc/guides/sample_app_ug/l3_forward_power_man.rst: update Liang Ma
2018-10-19 11:07 ` [dpdk-dev] [PATCH v12 5/5] doc: update release notes for empty poll library Liang Ma
2018-10-22 12:41 ` Kovacevic, Marko
2018-10-25 23:39 ` Thomas Monjalon
2018-10-25 23:22 ` [dpdk-dev] [PATCH v12 1/5] lib/librte_power: traffic pattern aware power control Thomas Monjalon
2018-10-25 23:32 ` Thomas Monjalon
2018-10-25 23:54 ` Thomas Monjalon
2018-10-25 23:55 ` Thomas Monjalon
2018-10-26 13:34 ` Liang, Ma
2018-10-01 10:06 ` [dpdk-dev] [PATCH v9 4/4] doc/guides/sample_app_ug/l3_forward_power_man.rst: empty poll update Liang Ma
2018-06-14 10:59 ` [dpdk-dev] [PATCH v1 1/2] lib/librte_power: traffic pattern aware power control Hunt, David
2018-06-18 16:11 ` Liang, Ma
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