From 4b7c0d64c805ca0e7d98c45736c0dd514ad2610d Mon Sep 17 00:00:00 2001
From: Malte Sandstede <malte@sandstede.com>
Date: Thu, 6 Jul 2023 20:45:02 +0200
Subject: [PATCH] Add GC metric `last_incremental_sweep` (#50190)

* Add GC metric `last_incremental_sweep`

* Update gc.c

* Update gc.c
---
 base/timing.jl | 1 +
 src/gc.c       | 3 +++
 src/gc.h       | 1 +
 3 files changed, 5 insertions(+)

diff --git a/base/timing.jl b/base/timing.jl
index d089a43071e78..aeca790bce7e9 100644
--- a/base/timing.jl
+++ b/base/timing.jl
@@ -25,6 +25,7 @@ struct GC_Num
     total_sweep_time  ::Int64
     total_mark_time   ::Int64
     last_full_sweep ::Int64
+    last_incremental_sweep ::Int64
 end
 
 gc_num() = ccall(:jl_gc_num, GC_Num, ())
diff --git a/src/gc.c b/src/gc.c
index 7d847195dce8c..d3edbdda23939 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -3302,6 +3302,9 @@ static int _jl_gc_collect(jl_ptls_t ptls, jl_gc_collection_t collection)
     if (sweep_full) {
         gc_num.last_full_sweep = gc_end_time;
     }
+    else {
+        gc_num.last_incremental_sweep = gc_end_time;
+    }
 
     size_t heap_size = jl_atomic_load_relaxed(&gc_heap_stats.heap_size);
     double target_allocs = 0.0;
diff --git a/src/gc.h b/src/gc.h
index 4bfe5dc328e9d..1328ef88c2d7c 100644
--- a/src/gc.h
+++ b/src/gc.h
@@ -83,6 +83,7 @@ typedef struct {
     uint64_t    total_sweep_time;
     uint64_t    total_mark_time;
     uint64_t    last_full_sweep;
+    uint64_t    last_incremental_sweep;
 } jl_gc_num_t;
 
 // Array chunks (work items representing suffixes of