diff --git a/Documentation/config/core.txt b/Documentation/config/core.txt
index 75538d27e7..1a188db620 100644
--- a/Documentation/config/core.txt
+++ b/Documentation/config/core.txt
@@ -577,8 +577,9 @@ the `GIT_NOTES_REF` environment variable.  See linkgit:git-notes[1].
 
 core.commitGraph::
 	If true, then git will read the commit-graph file (if it exists)
-	to parse the graph structure of commits. Defaults to false. See
-	linkgit:git-commit-graph[1] for more information.
+	to parse the graph structure of commits. Defaults to false, unless
+	`core.size=large`. See linkgit:git-commit-graph[1] for more
+	information.
 
 core.useReplaceRefs::
 	If set to `false`, behave as if the `--no-replace-objects`
@@ -601,3 +602,14 @@ core.abbrev::
 	in your repository, which hopefully is enough for
 	abbreviated object names to stay unique for some time.
 	The minimum length is 4.
+
+core.size::
+	When specified as "large", change the default values of some config
+	variables to improve performance in a large repository. If a variable
+	is specified explicitly, the explicit value will override these
+	defaults:
++
+* `core.commitGraph=true` enables reading commit-graph files.
++
+* `gc.writeCommitGraph=true` eneables writing commit-graph files during
+`git gc`.
diff --git a/Documentation/config/gc.txt b/Documentation/config/gc.txt
index 02b92b18b5..680721ebbb 100644
--- a/Documentation/config/gc.txt
+++ b/Documentation/config/gc.txt
@@ -63,8 +63,8 @@ gc.writeCommitGraph::
 	If true, then gc will rewrite the commit-graph file when
 	linkgit:git-gc[1] is run. When using `git gc --auto`
 	the commit-graph will be updated if housekeeping is
-	required. Default is false. See linkgit:git-commit-graph[1]
-	for details.
+	required. Default is false, unless `core.size=large`.
+	See linkgit:git-commit-graph[1] for details.
 
 gc.logExpiry::
 	If the file gc.log exists, then `git gc --auto` will print
diff --git a/Makefile b/Makefile
index 8a7e235352..2d3499d7ac 100644
--- a/Makefile
+++ b/Makefile
@@ -967,6 +967,7 @@ LIB_OBJS += refspec.o
 LIB_OBJS += ref-filter.o
 LIB_OBJS += remote.o
 LIB_OBJS += replace-object.o
+LIB_OBJS += repo-settings.o
 LIB_OBJS += repository.o
 LIB_OBJS += rerere.o
 LIB_OBJS += resolve-undo.o
diff --git a/builtin/gc.c b/builtin/gc.c
index 8943bcc300..6281aad961 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -27,6 +27,7 @@
 #include "pack-objects.h"
 #include "blob.h"
 #include "tree.h"
+#include "repo-settings.h"
 
 #define FAILED_RUN "failed to run %s"
 
@@ -41,7 +42,6 @@ static int aggressive_depth = 50;
 static int aggressive_window = 250;
 static int gc_auto_threshold = 6700;
 static int gc_auto_pack_limit = 50;
-static int gc_write_commit_graph;
 static int detach_auto = 1;
 static timestamp_t gc_log_expire_time;
 static const char *gc_log_expire = "1.day.ago";
@@ -148,7 +148,6 @@ static void gc_config(void)
 	git_config_get_int("gc.aggressivedepth", &aggressive_depth);
 	git_config_get_int("gc.auto", &gc_auto_threshold);
 	git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
-	git_config_get_bool("gc.writecommitgraph", &gc_write_commit_graph);
 	git_config_get_bool("gc.autodetach", &detach_auto);
 	git_config_get_expiry("gc.pruneexpire", &prune_expire);
 	git_config_get_expiry("gc.worktreepruneexpire", &prune_worktrees_expire);
@@ -685,7 +684,8 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
 		clean_pack_garbage();
 	}
 
-	if (gc_write_commit_graph)
+	prepare_repo_settings(the_repository);
+	if (the_repository->settings->gc_write_commit_graph == 1)
 		write_commit_graph_reachable(get_object_directory(), 0,
 					     !quiet && !daemonized);
 
diff --git a/commit-graph.c b/commit-graph.c
index 7c5e54875f..b09c465a7a 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -16,6 +16,7 @@
 #include "hashmap.h"
 #include "replace-object.h"
 #include "progress.h"
+#include "repo-settings.h"
 
 #define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */
 #define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
@@ -311,7 +312,6 @@ static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
 static int prepare_commit_graph(struct repository *r)
 {
 	struct object_directory *odb;
-	int config_value;
 
 	if (git_env_bool(GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD, 0))
 		die("dying as requested by the '%s' variable on commit-graph load!",
@@ -321,9 +321,10 @@ static int prepare_commit_graph(struct repository *r)
 		return !!r->objects->commit_graph;
 	r->objects->commit_graph_attempted = 1;
 
+	prepare_repo_settings(r);
+
 	if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
-	    (repo_config_get_bool(r, "core.commitgraph", &config_value) ||
-	    !config_value))
+	    r->settings->core_commit_graph != 1)
 		/*
 		 * This repository is not configured to use commit graphs, so
 		 * do not load one. (But report commit_graph_attempted anyway
diff --git a/repo-settings.c b/repo-settings.c
new file mode 100644
index 0000000000..6f5e18d92e
--- /dev/null
+++ b/repo-settings.c
@@ -0,0 +1,44 @@
+#include "cache.h"
+#include "repository.h"
+#include "config.h"
+#include "repo-settings.h"
+
+
+#define UPDATE_DEFAULT(s,v) if (s != -1) { s = v; }
+
+static int git_repo_config(const char *key, const char *value, void *cb)
+{
+	struct repo_settings *rs = (struct repo_settings *)cb;
+
+	if (!strcmp(key, "core.size")) {
+		if (!strcmp(value, "large")) {
+			UPDATE_DEFAULT(rs->core_commit_graph, 1);
+			UPDATE_DEFAULT(rs->gc_write_commit_graph, 1);
+		}
+		return 0;
+	}
+	if (!strcmp(key, "core.commitgraph")) {
+		rs->core_commit_graph = git_config_bool(key, value);
+		return 0;
+	}
+	if (!strcmp(key, "gc.writecommitgraph")) {
+		rs->gc_write_commit_graph = git_config_bool(key, value);
+		return 0;
+	}
+
+	return 1;
+}
+
+void prepare_repo_settings(struct repository *r)
+{
+	if (r->settings)
+		return;
+
+	r->settings = xmalloc(sizeof(*r->settings));
+
+	/* Defaults */
+	r->settings->core_commit_graph = -1;
+	r->settings->gc_write_commit_graph = -1;
+
+	repo_config(r, git_repo_config, r->settings);
+}
diff --git a/repo-settings.h b/repo-settings.h
new file mode 100644
index 0000000000..11d08648e1
--- /dev/null
+++ b/repo-settings.h
@@ -0,0 +1,13 @@
+#ifndef REPO_SETTINGS_H
+#define REPO_SETTINGS_H
+
+struct repo_settings {
+	char core_commit_graph;
+	char gc_write_commit_graph;
+};
+
+struct repository;
+
+void prepare_repo_settings(struct repository *r);
+
+#endif /* REPO_SETTINGS_H */
diff --git a/repository.h b/repository.h
index 4fb6a5885f..352afc9cd8 100644
--- a/repository.h
+++ b/repository.h
@@ -4,6 +4,7 @@
 #include "path.h"
 
 struct config_set;
+struct repo_settings;
 struct git_hash_algo;
 struct index_state;
 struct lock_file;
@@ -72,6 +73,8 @@ struct repository {
 	 */
 	char *submodule_prefix;
 
+	struct repo_settings *settings;
+
 	/* Subsystems */
 	/*
 	 * Repository's config which contains key-value pairs from the usual
