RUN-636: Add per-call context instruction counter

dfinity · Jun 23, 2023 · 72502c0 · 72502c0
1 parent f1c006b
commit 72502c0
Show file tree

Hide file tree

Showing 2 changed files with 7 additions and 6 deletions.
diff --git a/spec/changelog.adoc b/spec/changelog.adoc
@@ -4,6 +4,7 @@
 [#unreleased]
 === ∞ (unreleased)
 * Spec: User delegations include a principal scope
+* Spec: Add per-call context performance counter
 
 [#0_18_9]
 === 0.18.9 (2022-12-06)

diff --git a/spec/index.adoc b/spec/index.adoc
@@ -1461,19 +1461,17 @@ Passing zero as an argument to the function deactivates the timer and thus preve
 [#system-api-performance-counter]
 === Performance counter
 
-The canister can query the "performance counter", which is a deterministic monotonically increasing integer approximating the amount of work the canister has done since the beginning of the current execution.
+The canister can query the "performance counter" to get a deterministic integer approximation of different canister activities. Developers might use this data to profile and optimize the canister performance.
 
 `+ic0.performance_counter : (counter_type : i32) -> i64+`
 
 The argument `type` decides which performance counter to return:
 
-* 0 : instruction counter. The number of WebAssembly instructions the system has determined that the canister has executed.
+* 0 : message execution instruction counter. The number of WebAssembly instructions the canister has executed since the beginning of the current message execution. The system resets this counter at the beginning of each <<rule-message-execution>>.
 
-In the future, we might expose more performance counters.
+* 1 : call context instruction counter. The number of WebAssembly instructions the canister has executed since the creation of the current call context. The system sets this counter to zero during the <<call-context-creation>>. The counter is monotonically increasing across a few <<rule-message-execution,message executions>>, until the <<call-context-removal,call context is removed>>.
 
-The system resets the counter at the beginning of each <<entry-points>> invocation.
-
-The main purpose of this counter is to facilitate in-canister performance profiling.
+In the future, the IC might expose more performance counters.
 
 [#system-api-controller-check]
 === Controller check
@@ -2857,6 +2855,7 @@ State after::
 ....
 
 
+[#call-context-creation]
 ==== Call context creation
 
 Before invoking a heartbeat, a global timer, or a message to a public entry point, a call context is created for bookkeeping purposes.
@@ -3169,6 +3168,7 @@ S with
       }
 ....
 
+[#call-context-removal]
 ==== Call context removal
 
 If there is no call, downstream call context, or response that references a call context, and the call context does not need to respond (because it has already responded or its origin is a system task that does not await a response), then the call context can be removed.