Add benchmarks-based signature verification gas costs

Author: maurolacy

packages/vm/src/imports.rs

@@ -1,5 +1,6 @@
 //! Import implementations
 
+use std::cmp::max;
 use std::convert::TryInto;
 
 use cosmwasm_crypto::{
@@ -27,10 +28,17 @@ use crate::sections::encode_sections;
 use crate::serde::to_vec;
 use crate::GasInfo;
 
-const GAS_COST_SECP256K1_VERIFY_SIGNATURE: u64 = 100;
-const GAS_COST_SECP256K1_RECOVER_PUBKEY_SIGNATURE: u64 = 100;
-const GAS_COST_VERIFY_ED25519_SIGNATURE: u64 = 100;
-const GAS_COST_BATCH_VERIFY_ED25519_SIGNATURE: u64 = GAS_COST_VERIFY_ED25519_SIGNATURE / 3;
+// 1000 Cosmos SDK * 100 CosmWasm factor (~154 us in crypto benchmarks)
+const GAS_COST_SECP256K1_VERIFY: u64 = 100000;
+
+// Gas costs relative to secp256k1_verify cost
+const GAS_COST_SECP256K1_RECOVER_PUBKEY: u64 = 105195; // 100_000 * 162 us / 154 us
+const GAS_COST_ED25519_VERIFY: u64 = 40909; // 100_000 * 63 us / 154 us
+
+// Gas costs relative to ed25519_verify cost
+// From https://docs.rs/ed25519-zebra/2.2.0/ed25519_zebra/batch/index.html
+const GAS_COST_ED25519_BATCH_DIVISOR: u64 = 2;
+const GAS_COST_ED25519_BATCH_ONE_PUBKEY_DIVISOR: u64 = 4;
 
 /// A kibi (kilo binary)
 const KI: usize = 1024;
@@ -296,7 +304,7 @@ fn do_secp256k1_verify<A: BackendApi, S: Storage, Q: Querier>(
     let pubkey = read_region(&env.memory(), pubkey_ptr, ECDSA_PUBKEY_MAX_LEN)?;
 
     let result = secp256k1_verify(&hash, &signature, &pubkey);
-    let gas_info = GasInfo::with_cost(GAS_COST_SECP256K1_VERIFY_SIGNATURE);
+    let gas_info = GasInfo::with_cost(GAS_COST_SECP256K1_VERIFY);
     process_gas_info::<A, S, Q>(env, gas_info)?;
     Ok(result.map_or_else(
         |err| match err {
@@ -327,7 +335,7 @@ fn do_secp256k1_recover_pubkey<A: BackendApi, S: Storage, Q: Querier>(
     };
 
     let result = secp256k1_recover_pubkey(&hash, &signature, recover_param);
-    let gas_info = GasInfo::with_cost(GAS_COST_SECP256K1_RECOVER_PUBKEY_SIGNATURE);
+    let gas_info = GasInfo::with_cost(GAS_COST_SECP256K1_RECOVER_PUBKEY);
     process_gas_info::<A, S, Q>(env, gas_info)?;
     match result {
         Ok(pubkey) => {
@@ -358,7 +366,7 @@ fn do_ed25519_verify<A: BackendApi, S: Storage, Q: Querier>(
     let pubkey = read_region(&env.memory(), pubkey_ptr, EDDSA_PUBKEY_LEN)?;
 
     let result = ed25519_verify(&message, &signature, &pubkey);
-    let gas_info = GasInfo::with_cost(GAS_COST_VERIFY_ED25519_SIGNATURE);
+    let gas_info = GasInfo::with_cost(GAS_COST_ED25519_VERIFY);
     process_gas_info::<A, S, Q>(env, gas_info)?;
     Ok(result.map_or_else(
         |err| match err {
@@ -402,8 +410,15 @@ fn do_ed25519_batch_verify<A: BackendApi, S: Storage, Q: Querier>(
     let public_keys = decode_sections(&public_keys);
 
     let result = ed25519_batch_verify(&messages, &signatures, &public_keys);
-    let gas_info =
-        GasInfo::with_cost(GAS_COST_BATCH_VERIFY_ED25519_SIGNATURE * signatures.len() as u64);
+    let divisor = if public_keys.len() == 1 {
+        GAS_COST_ED25519_BATCH_ONE_PUBKEY_DIVISOR
+    } else {
+        GAS_COST_ED25519_BATCH_DIVISOR
+    };
+    let gas_info = GasInfo::with_cost(max(
+        GAS_COST_ED25519_VERIFY,
+        GAS_COST_ED25519_VERIFY / divisor * signatures.len() as u64,
+    ));
     process_gas_info::<A, S, Q>(env, gas_info)?;
     Ok(result.map_or_else(|err| err.code(), |valid| (!valid).into()))
 }