active_slot_coeff ignored in performance calculation.

[KtorZ]

Context

Information	-
Version	N/A
Platform	All
Installation	N/A

From Genesis Praos:

[...]
to be independently selected as a leader for a particular slot sl_j with probability p_i depending only on its relative stake. (In this static-stake analysis, relative stake is simply determined by the genesis block B0.)

The exact relationship between p_i and the relative stake α_i is determined by a parameter f of the protocol which we refer to as the active slots coefficient.

Specifically, p_i = φ_f(α_i) = 1 − ( 1 − f) α_i
[...]

From this, we understand that the probability of being elected is not only proportional to the stake, but also depends on this genesis parameter active slots coefficient (referred to as consensus_genesis_praos_active_slot_coeff in Jörmungandr configuration). This parameter has to be taken into consideration for the performance calculation not to be completely off.

Steps to Reproduce

1. Query listStakePools API endpoint

Expected behavior

1. Pools that perform very well (like IOHK ones) have a performance close to 1.

Actual behavior

1. Their performance is 1/10th of that

---

Resolution

• Extract the active slot coefficient from the chain parameters, and use it to adjust the performance calculation ==> Account for "active slot coefficient" in apparent performance calculation #1189

---

QA

• Extended prop_performancesBounded01 to also use an arbitrary active slot coefficient ( https://github.com/input-output-hk/cardano-wallet/blob/master/lib/core/test/unit/Cardano/Pool/MetricsSpec.hs#L204 )

• Added an extra unit test to illustrate the influence of the active slot coefficient https://github.com/input-output-hk/cardano-wallet/blob/master/lib/core/test/unit/Cardano/Pool/MetricsSpec.hs#L249-L253

• Controlled result against nightly:

TOP 10 Pools on Nightly

[
    {
        "apparent_performance": 1,
        "metadata": { "ticker": "IOHK2" },
        "id": "05663389504cd649fdd6cfc406c31872c32399ae6721642245f76946e55bb1fe"
    },
    {
        "apparent_performance": 1,
        "metadata": { "ticker": "FRGL" },
        "id": "1171304154a20bd28cae430c7e9c915e5bdc1eec69893dc69d7267be7197ae21"
    },
    {
        "apparent_performance": 1,
        "metadata": { "ticker": "IOHK3" },
        "id": "26c1deb80f2e041fe5a6d67d3f4c4b27dde24ea532a11633ec0d6cfc14a880f7"
    },
    {
        "apparent_performance": 1,
        "metadata": { "ticker": "RELY" },
        "id": "27793e62100b6fefbbc4ea54af4bfb24454eb7c5e04b5e3ebe191ba0db8efd55"
    },
    {
        "apparent_performance": 1,
        "id": "3f096d23d43efaa13ec6d903304e23a2ef552cc460d39cdb1cafa233bc5394ef"
    },
    {
        "apparent_performance": 1,
        "metadata": { "ticker": "HEL" },
        "id": "46221fb809db63e408ce1751196705a88af6e27ccac1acb92b8b705dfbfceb6a"
    },
    {
        "apparent_performance": 1,
        "metadata": { "ticker": "COOL" },
        "id": "7062afd7fd83c372fc65438c302f3db23bd3404edc043e4806ec3ba6a486be3b"
    },
    {
        "apparent_performance": 1,
        "id": "8819ca23c3ac6865d6578350de0bcb072e797519410b923d18f56b61370d93ff"
    },
    {
        "apparent_performance": 1,
        "metadata": { "ticker": "JBREW" },
        "id": "8ca014edc250a888645dacf3e7803d9bf217148d2534e80ee99257479a074aa2"
    },
    {
        "apparent_performance": 1,
        "metadata": { "ticker": "247" },
        "id": "9d16d5dfb84296c54868050e0e9f3130632d9a3fe2aa4febd65cb5235a84557e"
    }
]

All pools performances seen on nightly

0
0.11336765496849342
0.17989919600079335
0.20586241451124396
0.3139972298831227
0.3583264647256367
0.5
0.5451975737056386
0.7106819593189653
0.7227635377048117
0.8973330307767313
0.9052103033417835
0.9480349364235434
0.9507090156555771
0.9583850034019517
0.9816576385996468
1