[CCInstr] Add a field in the task to record the time of last call

src/Makefile

@@ -46,7 +46,8 @@ SRCS := \
 	simplevector runtime_intrinsics precompile jloptions mtarraylist \
 	threading partr stackwalk gc gc-debug gc-pages gc-stacks gc-alloc-profiler gc-page-profiler method \
 	jlapi signal-handling safepoint timing subtype rtutils gc-heap-snapshot \
-	crc32c APInt-C processor ircode opaque_closure codegen-stubs coverage runtime_ccall
+	crc32c APInt-C processor ircode opaque_closure codegen-stubs coverage runtime_ccall \
+	cancellation-instrumentation
 
 RT_LLVMLINK :=
 CG_LLVMLINK :=

src/cancellation-instrumentation.cpp

@@ -0,0 +1,47 @@
+/*
+ * cancellation_instrumentation.cpp
+ *
+ *  Created on: 9 Mar 2024
+ *      Author: ddeleo
+ */
+#include "julia.h"
+#include "julia_internal.h"
+
+#include <iostream>
+#include <unistd.h>
+
+using namespace std;
+
+extern "C" {
+
+static uint64_t g_min_update_interval = 0;
+static uint64_t get_min_update_interval() {
+    // this is inherently thread-safe, but that's okay as we're only interested on a rough estimate
+    // for how many clock cycles correspond to 1 second, more or less.
+    if (g_min_update_interval == 0) {
+        // sleep can be interrupted by a signal before the expected sleep time. In this case it will
+        // return with a value != 0 and we repeat the measurement.
+        int rc = 0;
+        do {
+            uint64_t t0 = cycleclock();
+            rc = sleep(1); // 1 second
+            uint64_t t1 = cycleclock();
+            g_min_update_interval = t1 - t0;
+        } while (rc != 0);
+    }
+    return g_min_update_interval;
+}
+
+JL_DLLEXPORT bool update_epoch(bool force) {
+    jl_task_t *task = jl_current_task;
+    uint64_t t0 = task->instr_last_epoch;
+    uint64_t t1 = cycleclock();
+    if (!force && ((t1 - t0) <= get_min_update_interval())){
+        return false;
+    } else {
+        task->instr_last_epoch = t1;
+        return true;
+    }
+}
+
+} // extern C

src/julia.h

@@ -1960,6 +1960,9 @@ typedef struct _jl_task_t {
     uint16_t reentrant_timing; // How many times we've reentered timing
     unsigned int copy_stack:31; // sizeof stack for copybuf
     unsigned int started:1;
+
+// cancellation instrumentation:
+    uint64_t instr_last_epoch;
 } jl_task_t;
 
 #define JL_TASK_STATE_RUNNABLE 0

src/task.c

@@ -961,6 +961,10 @@ JL_DLLEXPORT jl_task_t *jl_new_task(jl_function_t *start, jl_value_t *completion
 #ifdef _COMPILER_ASAN_ENABLED_
     t->ctx.asan_fake_stack = NULL;
 #endif
+
+    // Cancellation instrumentation
+    t->instr_last_epoch = 0;
+
     return t;
 }