// Module included in the following assemblies:
//
// * scalability_and_performance/low_latency_tuning/cnf-performing-platform-verification-latency-tests.adoc

:_mod-docs-content-type: CONCEPT
[id="cnf-performing-end-to-end-tests-example-results-hwlatdetect_{context}"]
= Example hwlatdetect test results

[role="_abstract"]
To track the impact of changes made during testing, capture the raw data from each run along with a combined set of your optimal configuration settings. Retaining these metrics provides a comprehensive history of your test results.

You can capture the following types of results:

* Rough results that are gathered after each run to create a history of impact on any changes made throughout the test.

* The combined set of the rough tests with the best results and configuration settings.

.Example of good results
[source,terminal]
----
hwlatdetect: test duration 3600 seconds
detector: tracer
parameters:
Latency threshold: 10us
Sample window: 1000000us
Sample width: 950000us
Non-sampling period: 50000us
Output File: None

Starting test
test finished
Max Latency: Below threshold
Samples recorded: 0
----

The `hwlatdetect` tool only provides output if the sample exceeds the specified threshold.

.Example of bad results
[source,terminal]
----
hwlatdetect: test duration 3600 seconds
detector: tracer
parameters:Latency threshold: 10usSample window: 1000000us
Sample width: 950000usNon-sampling period: 50000usOutput File: None

Starting tests:1610542421.275784439, inner:78, outer:81
ts: 1610542444.330561619, inner:27, outer:28
ts: 1610542445.332549975, inner:39, outer:38
ts: 1610542541.568546097, inner:47, outer:32
ts: 1610542590.681548531, inner:13, outer:17
ts: 1610543033.818801482, inner:29, outer:30
ts: 1610543080.938801990, inner:90, outer:76
ts: 1610543129.065549639, inner:28, outer:39
ts: 1610543474.859552115, inner:28, outer:35
ts: 1610543523.973856571, inner:52, outer:49
ts: 1610543572.089799738, inner:27, outer:30
ts: 1610543573.091550771, inner:34, outer:28
ts: 1610543574.093555202, inner:116, outer:63
----

The output of `hwlatdetect` shows that multiple samples exceed the threshold. However, the same output can indicate different results based on the following factors:

* The duration of the test
* The number of CPU cores
* The host firmware settings

[WARNING]
====
Before proceeding with the next latency test, ensure that the latency reported by `hwlatdetect` meets the required threshold. Fixing latencies introduced by hardware might require you to contact the system vendor support.

Not all latency spikes are hardware related. Ensure that you tune the host firmware to meet your workload requirements. For more information, see "Setting firmware parameters for system tuning".
====
