Merge pull request #2152 from CosmWasm/chipshort/gas-benchmarking

Rebalance gas cost

Author: chipshort

CHANGELOG.md

@@ -78,6 +78,8 @@ and this project adheres to
 - cosmwasm-std: Deprecate "compact" serialization of `Binary`, `HexBinary`,
   `Checksum` ([#2125])
 - cosmwasm-vm: Update wasmer to 4.3.1 ([#2147], [#2153])
+- cosmwasm-vm: Rebalance gas costs for cryptographic functions and wasm
+  instructions. ([#2152])
 
 [#2044]: https://github.com/CosmWasm/cosmwasm/pull/2044
 [#2051]: https://github.com/CosmWasm/cosmwasm/pull/2051
@@ -88,6 +90,7 @@ and this project adheres to
 [#2108]: https://github.com/CosmWasm/cosmwasm/pull/2108
 [#2125]: https://github.com/CosmWasm/cosmwasm/pull/2125
 [#2147]: https://github.com/CosmWasm/cosmwasm/pull/2147
+[#2152]: https://github.com/CosmWasm/cosmwasm/pull/2152
 [#2153]: https://github.com/CosmWasm/cosmwasm/pull/2153
 
 ## [2.0.1] - 2024-04-03

contracts/crypto-verify/tests/integration.rs

@@ -21,7 +21,8 @@
 
 use cosmwasm_std::{Binary, Response, Uint128};
 use cosmwasm_vm::testing::{
-    instantiate, mock_env, mock_info, mock_instance, query, MockApi, MockQuerier, MockStorage,
+    instantiate, mock_env, mock_info, mock_instance_with_gas_limit, query, MockApi, MockQuerier,
+    MockStorage,
 };
 use cosmwasm_vm::{from_slice, Instance};
 use hex_literal::hex;
@@ -96,7 +97,7 @@ fn build_drand_message(round: u64, previous_signature: &[u8]) -> Vec<u8> {
 const DESERIALIZATION_LIMIT: usize = 20_000;
 
 fn setup() -> Instance<MockApi, MockStorage, MockQuerier> {
-    let mut deps = mock_instance(WASM, &[]);
+    let mut deps = mock_instance_with_gas_limit(WASM, 10_000_000_000);
     let msg = InstantiateMsg {};
     let info = mock_info(CREATOR, &[]);
     let res: Response = instantiate(&mut deps, mock_env(), info, msg).unwrap();

docs/GAS.md

@@ -29,6 +29,18 @@ gas and took 15ms on our CI system. The ideal cost per operation for this system
 is `10**12 / (96837752 / (15 / 1000))`: 154. This is rounded to 150 for
 simplicity.
 
+CosmWasm 2.1 update: All gas values were re-evaluated and adjusted to meet the 1
+Teragas/second target mentioned above. A rerun of the Argon2 test contract
+consumed 5270718300 gas with the previous cost of 150, so the operation count
+was `5270718300 / 150 = 35138122`. This took 6ms on our benchmark server, so the
+new cost per operation is `10**12 / (35138122 / (6 / 1000))`: 171. This is
+rounded to 170 for simplicity.
+
+Benchmarking system:
+
+- CPU: Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz (4 cores, 8 threads)
+- RAM: 32GB DDR4 2133 MHz
+
 Each machine is different, we know that. But the above target helps us in
 multiple ways:
 

packages/crypto/README.md

@@ -21,7 +21,7 @@ and [cosmwasm-std](`https://crates.io/crates/cosmwasm-std`) crates.
 
 ```
 cd packages/crypto
-cargo bench
+cargo bench --features std
 ```
 
 ## License

packages/crypto/benches/main.rs

@@ -157,12 +157,13 @@ where
             .map(|(secret_key, message)| *message * secret_key)
             .collect();
 
-        for i in 1..=two_pow_max {
-            let num_points = 2_usize.pow(i);
-            let messages = &messages[..num_points];
-            let keys = &public_keys[..num_points];
+        for i in 0..=two_pow_max {
+            let n = 2_usize.pow(i); // the number of pairings on the left hand side
+            let k = n + 1; // the number of pairings in total
+            let messages = &messages[..n];
+            let keys = &public_keys[..n];
             let aggregated_signature: G2Affine =
-                signatures[..num_points].iter().sum::<G2Projective>().into();
+                signatures[..n].iter().sum::<G2Projective>().into();
 
             let serialized_pubkeys: Vec<u8> = keys
                 .iter()
@@ -187,7 +188,7 @@ where
                 .serialize_compressed(&mut serialized_signature[..])
                 .unwrap();
 
-            group.bench_function(format!("bls12_381_pairing_equality_{num_points}"), |b| {
+            group.bench_function(format!("bls12_381_pairing_equality_k={k}"), |b| {
                 b.iter(|| {
                     let is_valid = black_box(bls12_381_pairing_equality(
                         &serialized_pubkeys,

packages/vm/src/environment.rs

@@ -42,55 +42,84 @@ pub struct GasConfig {
     /// ed25519 signature verification cost
     pub ed25519_verify_cost: u64,
     /// ed25519 batch signature verification cost
-    pub ed25519_batch_verify_cost: u64,
+    pub ed25519_batch_verify_cost: LinearGasCost,
     /// ed25519 batch signature verification cost (single public key)
-    pub ed25519_batch_verify_one_pubkey_cost: u64,
-    /// bls12-381 aggregate cost per point (g1)
-    pub bls12_381_aggregate_g1_per_point: u64,
-    /// bls12-381 aggregate cost per point (g2)
-    pub bls12_381_aggregate_g2_per_point: u64,
+    pub ed25519_batch_verify_one_pubkey_cost: LinearGasCost,
+    /// bls12-381 aggregate cost (g1)
+    pub bls12_381_aggregate_g1_cost: LinearGasCost,
+    /// bls12-381 aggregate cost (g2)
+    pub bls12_381_aggregate_g2_cost: LinearGasCost,
     /// bls12-381 hash to g1 cost
     pub bls12_381_hash_to_g1_cost: u64,
     /// bls12-381 hash to g2 cost
     pub bls12_381_hash_to_g2_cost: u64,
     /// bls12-381 pairing equality check cost
-    pub bls12_381_pairing_equality_cost: u64,
-    /// bls12-381 aggregated pairing equality check cost per point
-    /// (added on top of the base pairing equality check cost)
-    pub bls12_381_aggregated_pairing_equality_cost_per_pair: u64,
+    pub bls12_381_pairing_equality_cost: LinearGasCost,
 }
 
 impl Default for GasConfig {
     fn default() -> Self {
         // Target is 10^12 per second (see GAS.md), i.e. 10^6 gas per µ second.
         const GAS_PER_US: u64 = 1_000_000;
         Self {
-            // ~119 us in crypto benchmarks
-            secp256k1_verify_cost: 119 * GAS_PER_US,
-            // ~233 us in crypto benchmarks
-            secp256k1_recover_pubkey_cost: 233 * GAS_PER_US,
-            // ~374 us in crypto benchmarks
-            secp256r1_verify_cost: 374 * GAS_PER_US,
-            // ~834 us in crypto benchmarks
-            secp256r1_recover_pubkey_cost: 834 * GAS_PER_US,
-            // ~63 us in crypto benchmarks
-            ed25519_verify_cost: 63 * GAS_PER_US,
-            // Gas cost factors, relative to ed25519_verify cost
-            // From https://docs.rs/ed25519-zebra/2.2.0/ed25519_zebra/batch/index.html
-            ed25519_batch_verify_cost: 63 * GAS_PER_US / 2,
-            ed25519_batch_verify_one_pubkey_cost: 63 * GAS_PER_US / 4,
+            // ~96 us in crypto benchmarks
+            secp256k1_verify_cost: 96 * GAS_PER_US,
+            // ~194 us in crypto benchmarks
+            secp256k1_recover_pubkey_cost: 194 * GAS_PER_US,
+            // ~279 us in crypto benchmarks
+            secp256r1_verify_cost: 279 * GAS_PER_US,
+            // ~592 us in crypto benchmarks
+            secp256r1_recover_pubkey_cost: 592 * GAS_PER_US,
+            // ~35 us in crypto benchmarks
+            ed25519_verify_cost: 35 * GAS_PER_US,
+            // Calculated based on the benchmark results for `ed25519_batch_verify_{x}`.
+            ed25519_batch_verify_cost: LinearGasCost {
+                base: 24 * GAS_PER_US,
+                per_item: 21 * GAS_PER_US,
+            },
+            // Calculated based on the benchmark results for `ed25519_batch_verify_one_pubkey_{x}`.
+            ed25519_batch_verify_one_pubkey_cost: LinearGasCost {
+                base: 36 * GAS_PER_US,
+                per_item: 10 * GAS_PER_US,
+            },
             // just assume the production machines have more than 4 cores, so we can half that
-            bls12_381_aggregate_g1_per_point: 16 * GAS_PER_US / 2,
-            bls12_381_aggregate_g2_per_point: 33 * GAS_PER_US / 2,
-            bls12_381_hash_to_g1_cost: 324 * GAS_PER_US,
-            bls12_381_hash_to_g2_cost: 528 * GAS_PER_US,
-            // god i wish i was lying
-            bls12_381_pairing_equality_cost: 1038 * GAS_PER_US,
-            bls12_381_aggregated_pairing_equality_cost_per_pair: 108 * GAS_PER_US,
+            bls12_381_aggregate_g1_cost: LinearGasCost {
+                base: 136 * GAS_PER_US / 2,
+                per_item: 24 * GAS_PER_US / 2,
+            },
+            bls12_381_aggregate_g2_cost: LinearGasCost {
+                base: 207 * GAS_PER_US / 2,
+                per_item: 49 * GAS_PER_US / 2,
+            },
+            bls12_381_hash_to_g1_cost: 563 * GAS_PER_US,
+            bls12_381_hash_to_g2_cost: 871 * GAS_PER_US,
+            bls12_381_pairing_equality_cost: LinearGasCost {
+                base: 2112 * GAS_PER_US,
+                per_item: 163 * GAS_PER_US,
+            },
         }
     }
 }
 
+/// Linear gas cost model where the cost is linear in the number of items.
+///
+/// To calculate it, you sample the cost for a few different amounts of items and fit a line to it.
+/// Let `b` be that line of best fit. Then `base = b(0)` is the y-intercept and
+/// `per_item = b(1) - b(0)` the slope.
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub struct LinearGasCost {
+    /// This is a flat part of the cost, charged once per batch.
+    base: u64,
+    /// This is the cost per item in the batch.
+    per_item: u64,
+}
+
+impl LinearGasCost {
+    pub fn total_cost(&self, items: u64) -> u64 {
+        self.base + self.per_item * items
+    }
+}
+
 /** context data **/
 
 #[derive(Clone, PartialEq, Eq, Debug, Default)]

packages/vm/src/imports.rs

@@ -1,6 +1,5 @@
 //! Import implementations
 
-use std::cmp::max;
 use std::marker::PhantomData;
 
 use cosmwasm_crypto::{
@@ -253,7 +252,7 @@ const BLS12_381_AGGREGATE_SUCCESS: u32 = 0;
 /// Return code (error code) for success when hashing to the curve
 const BLS12_381_HASH_TO_CURVE_SUCCESS: u32 = 0;
 
-/// Maximum size of continous points passed to aggregate functions
+/// Maximum size of continuous points passed to aggregate functions
 const BLS12_381_MAX_AGGREGATE_SIZE: usize = 2 * MI;
 
 /// Maximum size of the message passed to the hash-to-curve functions
@@ -278,7 +277,9 @@ pub fn do_bls12_381_aggregate_g1<
 
     let estimated_point_count = (g1s.len() / BLS12_381_G1_POINT_LEN) as u64;
     let gas_info = GasInfo::with_cost(
-        data.gas_config.bls12_381_aggregate_g1_per_point * estimated_point_count,
+        data.gas_config
+            .bls12_381_aggregate_g1_cost
+            .total_cost(estimated_point_count),
     );
     process_gas_info(data, &mut store, gas_info)?;
 
@@ -322,7 +323,9 @@ pub fn do_bls12_381_aggregate_g2<
 
     let estimated_point_count = (g2s.len() / BLS12_381_G2_POINT_LEN) as u64;
     let gas_info = GasInfo::with_cost(
-        data.gas_config.bls12_381_aggregate_g2_per_point * estimated_point_count,
+        data.gas_config
+            .bls12_381_aggregate_g2_cost
+            .total_cost(estimated_point_count),
     );
     process_gas_info(data, &mut store, gas_info)?;
 
@@ -369,15 +372,18 @@ pub fn do_bls12_381_pairing_equality<
     let r = read_region(&memory, r_ptr, BLS12_381_G1_POINT_LEN)?;
     let s = read_region(&memory, s_ptr, BLS12_381_G2_POINT_LEN)?;
 
-    let estimated_point_count = (ps.len() / BLS12_381_G1_POINT_LEN) as u64;
-    let additional_cost = data
-        .gas_config
-        .bls12_381_aggregated_pairing_equality_cost_per_pair
-        // Add one since we do not include any pairs in the base benchmark, and we always need to add one for the `r` and `s` pair.
-        * (estimated_point_count  + 1);
+    // The values here are only correct if ps and qs can be divided by the point size.
+    // They are good enough for gas since we error in `bls12_381_pairing_equality` if the inputs are
+    // not properly formatted.
+    let estimated_n = (ps.len() / BLS12_381_G1_POINT_LEN) as u64;
+    // The number of parings to compute (`n` on the left hand side and `k = n + 1` in total)
+    let estimated_k = estimated_n + 1;
 
-    let gas_info =
-        GasInfo::with_cost(data.gas_config.bls12_381_pairing_equality_cost + additional_cost);
+    let gas_info = GasInfo::with_cost(
+        data.gas_config
+            .bls12_381_pairing_equality_cost
+            .total_cost(estimated_k),
+    );
     process_gas_info(data, &mut store, gas_info)?;
 
     let code = match bls12_381_pairing_equality(&ps, &qs, &r, &s) {
@@ -729,11 +735,11 @@ pub fn do_ed25519_batch_verify<
     let public_keys = decode_sections(&public_keys);
 
     let gas_cost = if public_keys.len() == 1 {
-        data.gas_config.ed25519_batch_verify_one_pubkey_cost
+        &data.gas_config.ed25519_batch_verify_one_pubkey_cost
     } else {
-        data.gas_config.ed25519_batch_verify_cost
-    } * signatures.len() as u64;
-    let gas_info = GasInfo::with_cost(max(gas_cost, data.gas_config.ed25519_verify_cost));
+        &data.gas_config.ed25519_batch_verify_cost
+    };
+    let gas_info = GasInfo::with_cost(gas_cost.total_cost(signatures.len() as u64));
     process_gas_info(data, &mut store, gas_info)?;
     let result = ed25519_batch_verify(&mut OsRng, &messages, &signatures, &public_keys);
     let code = match result {

packages/vm/src/instance.rs

@@ -914,7 +914,7 @@ mod tests {
 
         let report2 = instance.create_gas_report();
         assert_eq!(report2.used_externally, 251);
-        assert_eq!(report2.used_internally, 8461548);
+        assert_eq!(report2.used_internally, 12109530);
         assert_eq!(report2.limit, LIMIT);
         assert_eq!(
             report2.remaining,
@@ -1105,7 +1105,7 @@ mod tests {
             .unwrap();
 
         let init_used = orig_gas - instance.get_gas_left();
-        assert_eq!(init_used, 8461799);
+        assert_eq!(init_used, 12109781);
     }
 
     #[test]
@@ -1130,7 +1130,7 @@ mod tests {
             .unwrap();
 
         let execute_used = gas_before_execute - instance.get_gas_left();
-        assert_eq!(execute_used, 11181706);
+        assert_eq!(execute_used, 12658786);
     }
 
     #[test]
@@ -1173,6 +1173,6 @@ mod tests {
         );
 
         let query_used = gas_before_query - instance.get_gas_left();
-        assert_eq!(query_used, 7142556);
+        assert_eq!(query_used, 8094896);
     }
 }

packages/vm/src/testing/mock.rs

@@ -11,8 +11,13 @@ use crate::backend::unwrap_or_return_with_gas;
 use crate::{Backend, BackendApi, BackendError, BackendResult, GasInfo};
 
 pub const MOCK_CONTRACT_ADDR: &str = "cosmwasmcontract"; // TODO: use correct address
-const GAS_COST_HUMANIZE: u64 = 44; // TODO: these seem very low
-const GAS_COST_CANONICALIZE: u64 = 55;
+/// Default gas multiplier in wasmd.
+/// See https://github.com/CosmWasm/wasmd/blob/v0.51.0/x/wasm/types/gas_register.go#L34
+const WASMD_GAS_MULTIPLIER: u64 = 140_000;
+/// See https://github.com/CosmWasm/wasmd/blob/v0.51.0/x/wasm/keeper/api.go#L27
+const GAS_COST_HUMANIZE: u64 = 4 * WASMD_GAS_MULTIPLIER;
+/// See https://github.com/CosmWasm/wasmd/blob/v0.51.0/x/wasm/keeper/api.go#L28
+const GAS_COST_CANONICALIZE: u64 = 5 * WASMD_GAS_MULTIPLIER;
 
 /// Default prefix used when creating Bech32 encoded address.
 const BECH32_PREFIX: &str = "cosmwasm";

packages/vm/src/wasm_backend/engine.rs

@@ -23,7 +23,7 @@ fn cost(_operator: &Operator) -> u64 {
     // In https://github.com/CosmWasm/cosmwasm/pull/1042 a profiler is developed to
     // identify runtime differences between different Wasm operation, but this is not yet
     // precise enough to derive insights from it.
-    150
+    170
 }
 
 /// Use Cranelift as the compiler backend if the feature is enabled