Expose GC end timestamp

1 files changed, 20 insertions, 5 deletions

diff --git a/cbits/hook.c b/cbits/hook.c
index e05ccd4..2175be4 100644
--- a/cbits/hook.c
+++ b/cbits/hook.c
@@ -1,5 +1,6 @@
 #include "Rts.h"
 #include <string.h>
+#include <time.h>
 
 // needs C11
 #include <threads.h>
@@ -12,6 +13,9 @@ extern RtsConfig rtsConfig;
 
 // A copy of GCDetails_ with known structure that can be depended on by the Haskell code.
 struct ShadowDetails {
+	int64_t timestamp_sec;
+	int64_t timestamp_nsec;
+
 	// The generation number of this GC
 	uint32_t gen;
 	// Number of threads used in this GC
@@ -106,13 +110,21 @@ static struct ShadowDetails *detlog = NULL;
 // --------
 
 static void hook_callback(const struct GCDetails_ *details) {
-	static bool alloc_failed = false;
+	static bool fatal_failure = false;
+
+	if (fatal_failure) goto cleanup_no_mutex;
 
-	if (alloc_failed) goto cleanup_no_mutex;
+	// Do this now already, before waiting on the mutex
+	struct timespec now;
+	if (clock_gettime(CLOCK_MONOTONIC, &now) != 0) {
+		perror("clock_gettime");
+		fatal_failure = true;
+		goto cleanup_no_mutex;
+	}
 
 	if (mtx_lock(&detlog_mutex) != thrd_success) {
 		fprintf(stderr, "ghc-gc-hook: ERROR: Mutex lock failed\n");
-		alloc_failed = true;  // dumb proxy for "don't do anything anymore please"
+		fatal_failure = true;
 		goto cleanup_no_mutex;
 	}
 
@@ -123,12 +135,15 @@ static void hook_callback(const struct GCDetails_ *details) {
 		detlog = realloc(detlog, detlog_capacity * sizeof(detlog[0]));
 		if (detlog == NULL || detlog_capacity == 0) {  // also check for overflow here
 			fprintf(stderr, "ghc-gc-hook: ERROR: Could not allocate memory for GC log hook\n");
-			alloc_failed = true;
+			fatal_failure = true;
 			goto cleanup;
 		}
 	}
 
-	shadow_copy(&detlog[detlog_length], details);
+	struct ShadowDetails *dst = &detlog[detlog_length];
+	dst->timestamp_sec = now.tv_sec;
+	dst->timestamp_nsec = now.tv_nsec;
+	shadow_copy(dst, details);
 	detlog_length++;
 
 cleanup: