-Methodology
-===========
+Performance Trending Methodology
+================================
+.. _trending_methodology:
+
+Continuous Trending and Analysis
+--------------------------------
+
+This document describes a high-level design of a system for continuous
+performance measuring, trending and change detection for FD.io VPP SW
+data plane. It builds upon the existing FD.io CSIT framework with
+extensions to its throughput testing methodology, CSIT data analytics
+engine (PAL – Presentation-and-Analytics-Layer) and associated Jenkins
+jobs definitions.
+
+Proposed design replaces existing CSIT performance trending jobs and
+tests with new Performance Trending (PT) CSIT module and separate
+Performance Analysis (PA) module ingesting results from PT and
+analysing, detecting and reporting any performance anomalies using
+historical trending data and statistical metrics. PA does also produce
+trending dashboard and graphs with summary and drill-down views across
+all specified tests that can be reviewed and inspected regularly by
+FD.io developers and users community.
+
+Performance Trending Tests
+--------------------------
+
+Performance trending is currently relying on the Maximum Receive Rate
+(MRR) tests. MRR tests measure the packet forwarding rate under the
+maximum load offered by traffic generator over a set trial duration,
+regardless of packet loss. Maximum load for specified Ethernet frame
+size is set to the bi-directional link rate.
+
+Current parameters for performance trending MRR tests:
+
+- Ethernet frame sizes: 64B (78B for IPv6 tests) for all tests, IMIX for
+ selected tests (vhost, memif); all quoted sizes include frame CRC, but
+ exclude per frame transmission overhead of 20B (preamble, inter frame
+ gap).
+
+- Maximum load offered: 10GE and 40GE link (sub-)rates depending on NIC
+ tested, with the actual packet rate depending on frame size,
+ transmission overhead and traffic generator NIC forwarding capacity.
+
+ - For 10GE NICs the maximum packet rate load is 2* 14.88 Mpps for 64B,
+ a 10GE bi-directional link rate.
+ - For 40GE NICs the maximum packet rate load is 2* 18.75 Mpps for 64B,
+ a 40GE bi-directional link sub-rate limited by TG 40GE NIC used,
+ XL710.
+
+- Trial duration: 10sec.
+- Execution frequency: twice a day, every 12 hrs (02:00, 14:00 UTC).
+
+In the future if tested VPP configuration can handle the packet rate
+higher than bi-directional 10GE link rate, e.g. all IMIX tests and
+64B/78B multi-core tests, a higher maximum load will be offered
+(25GE|40GE|100GE).
+
+Performance Trend Analysis
+--------------------------
+
+All measured performance trend data is treated as time-series data that
+can be modelled using normal distribution. After trimming the outliers,
+the median and deviations from median are used for detecting performance
+change anomalies following the three-sigma rule of thumb (a.k.a.
+68-95-99.7 rule).
+
+Analysis Metrics
+````````````````
+
+Following statistical metrics are proposed as performance trend
+indicators over the rolling window of last <N> sets of historical
+measurement data:
+
+- Q1, Q2, Q3 : Quartiles, three points dividing a ranked data set
+ of <N> values into four equal parts, Q2 is the median of the data.
+- IQR = Q3 - Q1 : Inter Quartile Range, measure of variability, used
+ here to calculate and eliminate outliers.
+- Outliers : extreme values that are at least (1.5 * IQR) below Q1.
+
+ - Note: extreme values that are at least (1.5 * IQR) above Q3 are not
+ considered outliers, and are likely to be classified as
+ progressions.
+
+- TMA : Trimmed Moving Average, average across the data set of <N>
+ values without the outliers. Used here to calculate TMSD.
+- TMSD : Trimmed Moving Standard Deviation, standard deviation over the
+ data set of <N> values without the outliers,
+ requires calculating TMA. Used for anomaly detection.
+- TMM : Trimmed Moving Median, median across the data set of <N> values
+ excluding the outliers. Used as a trending value and as a reference
+ for anomaly detection.
+
+Outlier Detection
+`````````````````
+
+Outlier evaluation of test result of value <X> follows the definition
+from previous section:
+
+ Outlier Evaluation Formula Evaluation Result
+ ====================================================
+ X < (Q1 - 1.5 * IQR) Outlier
+ X >= (Q1 - 1.5 * IQR) Valid (For Trending)
+
+Anomaly Detection
+`````````````````
+
+To verify compliance of test result of valid value <X> against defined
+trend metrics and detect anomalies, three simple evaluation formulas are
+used:
+
+ Anomaly Compliance Evaluation
+ Evaluation Formula Confidence Level Result
+ =============================================================================
+ (TMM - 3 * TMSD) <= X <= (TMM + 3 * TMSD) 99.73% Normal
+ X < (TMM - 3 * TMSD) Anomaly Regression
+ X > (TMM + 3 * TMSD) Anomaly Progression
+
+TMM is used for the central trend reference point instead of TMA as it
+is more robust to anomalies.
+
+Trend Compliance
+````````````````
+
+Trend compliance metrics are targeted to provide an indication of trend
+changes over a short-term (i.e. weekly) and a long-term (i.e.
+quarterly), comparing the last trend value, TMM[last], to one from week
+ago, TMM[last - 1week] and to the maximum of trend values over last
+quarter except last week, max(TMM[(last - 3mths)..(last - 1week)]),
+respectively. This results in following trend compliance calculations:
+
+ Trend
+ Compliance Metric Change Formula V(alue) R(eference)
+ =============================================================================================
+ Short-Term Change ((V - R) / R) TMM[last] TMM[last - 1week]
+ Long-Term Change ((V - R) / R) TMM[last] max(TMM[(last - 3mths)..(last - 1week)])
+
+Performance Trend Presentation
+------------------------------
+
+Performance Dashboard
+`````````````````````
+
+Dashboard tables list a summary of per test-case VPP MRR performance
+trend and trend compliance metrics and detected number of anomalies.
+
+Separate tables are generated for tested VPP worker-thread-core
+combinations (1t1c, 2t2c, 4t4c). Test case names are linked to
+respective trending graphs for ease of navigation thru the test data.
+
+Trendline Graphs
+````````````````
+
+Trendline graphs show per test case measured MRR throughput values with
+associated trendlines. The graphs are constructed as follows:
+
+- X-axis represents performance trend job build Id (csit-vpp-perf-mrr-
+ daily-master-build).
+- Y-axis represents MRR throughput in Mpps.
+- Markers to indicate anomaly classification:
+
+ - Outlier - gray circle around MRR value point.
+ - Regression - red circle.
+ - Progression - green circle.
+
+In addition the graphs show dynamic labels while hovering over graph
+data points, representing (trend job build Id, MRR value) and the actual
+vpp build number (b<XXX>) tested.
+
+
+Jenkins Jobs Description
+------------------------
+
+Performance Trending (PT)
+`````````````````````````
+
+CSIT PT runs regular performance test jobs measuring and collecting MRR
+data per test case. PT is designed as follows:
+
+#. PT job triggers:
+
+ #. Periodic e.g. daily.
+ #. On-demand gerrit triggered.
+
+#. Measurements and data calculations per test case:
+
+ #. MRR Max Received Rate
+
+ #. Measured: Unlimited tolerance of packet loss.
+ #. Send packets at link rate, count total received packets, divide
+ by test trial period.
+
+#. Archive MRR per test case.
+#. Archive all counters collected at MRR.
+
+Performance Analysis (PA)
+`````````````````````````
+
+CSIT PA runs performance analysis including trendline calculation, trend
+compliance and anomaly detection using specified trend analysis metrics
+over the rolling window of last <N> sets of historical measurement data.
+PA is defined as follows:
+
+#. PA job triggers:
+
+ #. By PT job at its completion.
+ #. On-demand gerrit triggered.
+
+#. Download and parse archived historical data and the new data:
+
+ #. Download RF output.xml files from latest PT job and compressed
+ archived data.
+
+ #. Parse out the data filtering test cases listed in PA specification
+ (part of CSIT PAL specification file).
+
+ #. Evalute new data from latest PT job against the rolling window of
+ <N> sets of historical data for trendline calculation, anomaly
+ detection and short-term trend compliance. And against long-term
+ trendline metrics for long-term trend compliance.
+
+#. Calculate trend metrics for the rolling window of <N> sets of
+ historical data:
+
+ #. Calculate quartiles Q1, Q2, Q3.
+ #. Trim outliers using IQR.
+ #. Calculate TMA and TMSD.
+ #. Calculate normal trending range per test case based on TMM and
+ TMSD.
+
+#. Evaluate new test data against trend metrics:
+
+ #. If within the range of (TMA +/- 3*TMSD) => Result = Pass,
+ Reason = Normal. (to be updated base on final Jenkins code)
+ #. If below the range => Result = Fail, Reason = Regression.
+ #. If above the range => Result = Pass, Reason = Progression.
+
+#. Generate and publish results
+
+ #. Relay evaluation result to job result. (to be updated base on final
+ Jenkins code)
+ #. Generate a new set of trend summary dashboard and graphs.
+ #. Publish trend dashboard and graphs in html format on https://docs.fd.io/.
Code Review / csit.git / blobdiff