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Diffstat (limited to 'docs/user/AddingDebugKnobs.md')
| -rw-r--r-- | docs/user/AddingDebugKnobs.md | 43 |
1 files changed, 41 insertions, 2 deletions
diff --git a/docs/user/AddingDebugKnobs.md b/docs/user/AddingDebugKnobs.md index bcf3f1fcc6..83db52b375 100644 --- a/docs/user/AddingDebugKnobs.md +++ b/docs/user/AddingDebugKnobs.md @@ -12,12 +12,13 @@ The setting ranges from 0 to 65535 (0x0000 to 0xFFFF), where each bit represents * [Accessing Debug Knobs (dev side)](#accessing-debug-knobs-dev-side) * [Setting Debug Knobs (user side)](#setting-debug-knobs-user-side) * [Bit Manipulation Examples](#bit-manipulation-examples) -3. [Examples](#examples) +3. [Terminology and user communication](#terminology-and-user-communication) +4. [Examples](#examples) * [Example 1: Conditional Debug Logging](#example-1-conditional-debug-logging) * [Example 2: Performance Tuning](#example-2-performance-tuning) * [Example 3: Feature Gating](#example-3-feature-gating) -4. [Best Practices](#best-practices) +5. [Best Practices](#best-practices) --- @@ -77,6 +78,44 @@ To enable specific features, calculate the decimal value by setting the appropri * **Enable bits 0 and 1**: Value = 3 (2^0 + 2^1) * **Enable bit 15**: Value = 32768 (2^15) +## Terminology and user communication + +There are two main confusions when talking about knobs: + +### Whether it's zero-based or one-based + +Sometimes when an user reports: knobs 1 and 2 gets better performance, dev may get confuse whether he means the knobs 1 and 2 literally, or the 1st and 2nd knobs (knobs 0 and 1). + +Debug knobs are **zero-based**, which means: +* The first knob is the knob(0) (or knob0 henceforth), and the last one is the 15 (knob15, likewise) +* You can talk: "knob0 is enabled/disabled", "In this video i was using only knobs 0 and 2", etc. + +### Whether one is talking about the knob itself or about the entire parameter value (which represents all knobs) + +Sometimes when an user reports: knob 3 results, it's unclear whether he's referring to knob setting with value 3 (which means both knob 0 and 1 are enabled), or to knob(3) specifically. +Whenever you're instructing tests or reporting results, be precise about whether one you're talking to avoid confusion: + +### Setting based terminology + +ALWAYS use the word in PLURAL (knobs), without mentioning which one, to refer to the setting, aka multiple knobs at once: +Examples: +- **knobs=0**: no knobs enabled +- **knobs=1**: knob0 enabled, others disabled +- **knobs=2**: knob1 enabled, others disabled +- **knobs=3**: knobs 0 and 1 enabled, others disabled + +... + +### Knob based terminology + +Use the word in SINGULAR (knob), or in plural but referring which ones, when meaning multiple knobs at once: +Examples: +- **knob0**: knob 0 enabled, others disabled +- **knob1**: knob 1 enabled, others disabled +- **knobs 0 and 1**: knobs 0 and 1 enabled, others disabled + +... + ## Examples ### Example 1: Conditional Debug Logging |