[WIP] Base weights for Host implementations

PSPs/drafts/psp-49.md

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+# Base Weights
+
+- **PSP Number:** 49
+- **Authors:** Fabio Lama <fabio.lama@pm.me>
+- **Status:** Draft
+- **Created:** 2022-07-21
+- **Reference Implementation:** https://github.com/paritytech/substrate/pull/10918
+
+## Summary
+
+This standard sets weights on expensive resources such as computation, database
+access and bandwidth. The weights are determined by benchmarking the Substrate
+implementation that provides those resources to the Runtime and displays the
+recommended values that alternative implemenations to Substrate should adhere to
+in order to unify the cost of those resources and maintain a sustainable fee
+structure.
+
+## Motivation
+
+The Substrate implementation determined weights based on the resources that it
+provides to the Runtime for consumption, such as I/O, computation and network
+bandwidth. Given that alternative implementations are available and can be
+developed in the future, those weights should be reflected by those alternative
+implemenations so that the fee structure is justifiable for the diverse network
+of participants at large. The goal is to avoid situations where alternative
+implemenations are too strict or too loose in terms of costs of their resource
+requirements which could lead to bad economic outcomes and a fractured network
+of implemenations.
+
+...
+
+## Constants
+
+A weight of _1 unit_ corresponds to one picosecond. We define a list of
+constants to simplify the declaration of weights.
+
+| Symbol  | Weight                  | Description            |
+|---------|-------------------------|------------------------|
+| $w_s$   | 1'000'000'000'000       | Weight per second      |
+| $w_m$   | $$\frac{w_s}{1'000}$$   | Weight per millisecond |
+| $w_\mu$ | $$\frac{w_m}{1'000}$$   | Weight per microsecond |
+| $w_n$   | $$\frac{w_\mu}{1'000}$$ | Weight per nanosecond  |
+
+## Extrinsic
+
+The weight reflects the time it takes to execute a no-op extrinsic, such as
+`system_remark`, respectively an extrinsic that does not perform an operation.
+This weight indicates the _minimum (or base) requirement_ to execute an
+extrinsic.
+
+* `ExtrinsicBaseWeight` = $85'212 \times w_n$
+	*	| Stats   | Nanoseconds |
+		|---------|-------------|
+		| Min     | $84'940$    |
+		| Max     | $86'590$    |
+		| Average | $85'212$    |
+		| Median  | $85'156$    |
+		| Std-Dev | $243.25$    |
+
+	*	| Percentiles | Nanoseconds |
+		|-------------|-------------|
+		| 99th        | $86'269$    |
+		| 95th        | $85'510$    |
+		| 75th        | $85'216$    |
+
+# Block
+
+* `BlockExecutionWeight` = $5'797'172 \times w_n$
+	*	| Stats   | Nanoseconds |
+		|---------|-------------|
+		| Min     | $5'722'294$ |
+		| Max     | $5'960'144$ |
+		| Average | $5'797'172$ |
+		| Median  | $5'786'450$ |
+		| Std-Dev | $48'146.81$ |
+
+	*	| Percentiles | Nanoseconds |
+		|-------------|-------------|
+		| 99th        | $5'940'244$ |
+		| 95th        | $5'890'113$ |
+		| 75th        | $5'824'797$ |
+
+## Database
+
+...
+
+## RocksDb
+
+The weights reflect the time it takes to read and write one storage item. The
+value is calculated by multiplying the *Average* of all values with `1.1` and
+adding `0`.
+
+* `read` = $20'499 \times w_n$
+	*	| Stats   | Nanoseconds |
+		|---------|-------------|
+		| Min     | $5'015$     |
+		| Max     | $1'441'022$ |
+		| Average | $18'635$    |
+		| Median  | $17'795$    |
+		| Std-Dev | $4'829.75$  |
+
+	*	| Percentiles | Nanoseconds |
+		|-------------|-------------|
+		| 99th        | $32'074$    |
+		| 95th        | $26'658$    |
+		| 75th        | $19'363$    |
+
+
+* `write` = $83'471 \times w_n$
+	*	| Stats   | Nanoseconds  |
+		|---------|--------------|
+		| Min     | $16'368$     |
+		| Max     | $34'500'937$ |
+		| Average | $75'882$     |
+		| Median  | $74'236$     |
+		| Std-Dev | $64'706.41$  |
+
+	*	| Percentiles | Nanoseconds |
+		|-------------|-------------|
+		| 99th        | $111'151$   |
+		| 95th        | $92'666$    |
+		| 75th        | $80'297$    |
+
+## ParityDb
+
+The weights reflect the time it takes to read and write one storage item. The
+value is calculated by multiplying the *Average* of all values with `1.1` and
+adding `0`.
+
+* `read`: $11'826 \times w_n$
+	*	| Stats   | Nanoseconds  |
+		|---------|--------------|
+		| Min     | $4'611$      |
+		| Max     | $13'478'005$ |
+		| Average | $10'750$     |
+		| Median  | $10'655$     |
+		| Std-Dev | $12'214.49$  |
+
+	*	| Percentiles | Nanoseconds |
+		|-------------|-------------|
+		| 99th        | $14'451$    |
+		| 95th        | $12'588$    |
+		| 75th        | $11'200$    |
+
+
+* `write`: $38'053 \times w_n$
+	*	| Stats   | Nanoseconds  |
+		|---------|--------------|
+		| Min     | $8'023$      |
+		| Max     | $47'367'740$ |
+		| Average | $34'592$     |
+		| Median  | $32'703$     |
+		| Std-Dev | $49'417.24$  |
+
+	*	| Percentiles | Nanoseconds |
+		|-------------|-------------|
+		| 99th        | $69'379$    |
+		| 95th        | $47'168$    |
+		| 75th        | $35'252$    |
+
+## Copyright
+
+This document is placed in the [public domain](https://creativecommons.org/publicdomain/zero/1.0/).