fix: refine cycles cost calculation (#143)

* Refine cycles cost calculation * Update tests * Fix * Rename for clarity * Update unit test * Update Cargo.lock
dfinity · Jan 23, 2024 · 0b5c52d · 0b5c52d
1 parent 72741c7
commit 0b5c52d
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Showing 3 changed files with 27 additions and 15 deletions.
diff --git a/e2e/motoko/Main.mo b/e2e/motoko/Main.mo
@@ -19,8 +19,8 @@ shared ({ caller = installer }) actor class Main() {
 
         let canisterDetails = [
             // (`canister module`, `debug name`, `nodes in subnet`, `expected cycles for JSON-RPC call`)
-            (EvmRpcCanister, "default", 13, 65_923_200),
-            (EvmRpcFidicuaryCanister, "fiduciary", 28, 141_988_430),
+            (EvmRpcCanister, "default", 13, 61_898_400),
+            (EvmRpcFidicuaryCanister, "fiduciary", 28, 133_319_630),
         ];
         for ((canister, name, nodesInSubnet, expectedCycles) in canisterDetails.vals()) {
             Debug.print("Testing " # name # " canister...");

diff --git a/src/accounting.rs b/src/accounting.rs
@@ -41,8 +41,9 @@ pub fn get_http_request_cost(
         + INGRESS_OVERHEAD_BYTES;
     let base_cost = INGRESS_MESSAGE_RECEIVED_COST
         + INGRESS_MESSAGE_BYTE_RECEIVED_COST * ingress_bytes
-        + HTTP_OUTCALL_REQUEST_COST
-        + HTTP_OUTCALL_BYTE_RECEIVED_COST * (ingress_bytes + max_response_bytes as u128);
+        + HTTP_OUTCALL_REQUEST_BASE_COST
+        + HTTP_OUTCALL_REQUEST_COST_PER_BYTE * payload_size_bytes as u128
+        + HTTP_OUTCALL_RESPONSE_COST_PER_BYTE * max_response_bytes as u128;
     base_cost * (nodes_in_subnet as u128) / NODES_IN_DEFAULT_SUBNET as u128
 }
 
@@ -80,7 +81,7 @@ fn test_request_cost() {
             1000,
         );
         let estimated_cost_10_extra_bytes = base_cost
-            + 10 * (INGRESS_MESSAGE_BYTE_RECEIVED_COST + HTTP_OUTCALL_BYTE_RECEIVED_COST)
+            + 10 * (INGRESS_MESSAGE_BYTE_RECEIVED_COST + HTTP_OUTCALL_REQUEST_COST_PER_BYTE)
                 * nodes_in_subnet as u128
                 / NODES_IN_DEFAULT_SUBNET as u128;
         // Request body with 10 additional bytes should be within 1 cycle of expected cost (due to rounding)
@@ -155,15 +156,25 @@ fn test_candid_rpc_cost() {
     let provider = PROVIDERS.with(|providers| providers.borrow().get(&provider_id).unwrap());
 
     // Default subnet
-    assert_eq!(get_candid_rpc_cost(&provider, 0, 0), 54767387);
-    assert_eq!(get_candid_rpc_cost(&provider, 123, 123), 59170787);
-    assert_eq!(get_candid_rpc_cost(&provider, 123, 4567890), 47563947587);
-    assert_eq!(get_candid_rpc_cost(&provider, 890, 4567890), 47583429387);
+    assert_eq!(
+        [
+            get_candid_rpc_cost(&provider, 0, 0),
+            get_candid_rpc_cost(&provider, 123, 123),
+            get_candid_rpc_cost(&provider, 123, 4567890),
+            get_candid_rpc_cost(&provider, 890, 4567890),
+        ],
+        [51064987, 54828787, 47559605587, 47575098987]
+    );
 
     // Fiduciary subnet
     UNSTABLE_SUBNET_SIZE.with(|n| *n.borrow_mut() = NODES_IN_FIDUCIARY_SUBNET);
-    assert_eq!(get_candid_rpc_cost(&provider, 0, 0), 117960525);
-    assert_eq!(get_candid_rpc_cost(&provider, 123, 123), 127444772);
-    assert_eq!(get_candid_rpc_cost(&provider, 123, 4567890), 102445425572);
-    assert_eq!(get_candid_rpc_cost(&provider, 890, 4567890), 102487386372);
+    assert_eq!(
+        [
+            get_candid_rpc_cost(&provider, 0, 0),
+            get_candid_rpc_cost(&provider, 123, 123),
+            get_candid_rpc_cost(&provider, 123, 4567890),
+            get_candid_rpc_cost(&provider, 890, 4567890),
+        ],
+        [109986125, 118092772, 102436073572, 102469443972]
+    );
 }
diff --git a/src/constants.rs b/src/constants.rs
@@ -3,8 +3,9 @@ use cketh_common::eth_rpc_client::providers::{EthMainnetService, EthSepoliaServi
 pub const INGRESS_OVERHEAD_BYTES: u128 = 100;
 pub const INGRESS_MESSAGE_RECEIVED_COST: u128 = 1_200_000;
 pub const INGRESS_MESSAGE_BYTE_RECEIVED_COST: u128 = 2_000;
-pub const HTTP_OUTCALL_REQUEST_COST: u128 = 49_140_000;
-pub const HTTP_OUTCALL_BYTE_RECEIVED_COST: u128 = 10_400;
+pub const HTTP_OUTCALL_REQUEST_BASE_COST: u128 = 49_140_000;
+pub const HTTP_OUTCALL_REQUEST_COST_PER_BYTE: u128 = 5_200;
+pub const HTTP_OUTCALL_RESPONSE_COST_PER_BYTE: u128 = 10_400;
 
 // Minimum number of bytes charged for a URL; improves consistency of costs between providers
 pub const RPC_URL_MIN_COST_BYTES: u32 = 256;