diff mbox series

clk: make clk_core_lookup faster by using clk name hash

Message ID 20211005065948.10092-1-mark-pk.tsai@mediatek.com (mailing list archive)
State New, archived
Headers show
Series clk: make clk_core_lookup faster by using clk name hash | expand

Commit Message

Mark-PK Tsai (蔡沛剛) Oct. 5, 2021, 6:59 a.m. UTC 
Compare hash value before strcmp the full name to make
clk_core_lookup faster.

It make clk driver probe 30 percent faster on the platform
have 1483 registered clks and average clock name length 20.

Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
---
 drivers/clk/clk.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

Comments

Stephen Boyd Oct. 15, 2021, 12:44 a.m. UTC | #1 
Quoting Mark-PK Tsai (2021-10-04 23:59:49)
> Compare hash value before strcmp the full name to make
> clk_core_lookup faster.
> 
> It make clk driver probe 30 percent faster on the platform
> have 1483 registered clks and average clock name length 20.

Why is clk_core_lookup() a fast path for you?
Chen-Yu Tsai Oct. 18, 2021, 3:38 a.m. UTC | #2 
On Fri, Oct 15, 2021 at 8:44 AM Stephen Boyd <sboyd@kernel.org> wrote:
>
> Quoting Mark-PK Tsai (2021-10-04 23:59:49)
> > Compare hash value before strcmp the full name to make
> > clk_core_lookup faster.
> >
> > It make clk driver probe 30 percent faster on the platform
> > have 1483 registered clks and average clock name length 20.
>
> Why is clk_core_lookup() a fast path for you?

Maybe because the Mediatek clock driver still does global clk name matching
to resolve parents?
diff mbox series

Patch

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 65508eb89ec9..d5f65fda3db8 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -89,6 +89,7 @@  struct clk_core {
 	struct hlist_node	debug_node;
 #endif
 	struct kref		ref;
+	unsigned int		hash;
 };
 
 #define CREATE_TRACE_POINTS
@@ -292,16 +293,17 @@  struct clk_hw *clk_hw_get_parent(const struct clk_hw *hw)
 EXPORT_SYMBOL_GPL(clk_hw_get_parent);
 
 static struct clk_core *__clk_lookup_subtree(const char *name,
+					     unsigned int hash,
 					     struct clk_core *core)
 {
 	struct clk_core *child;
 	struct clk_core *ret;
 
-	if (!strcmp(core->name, name))
+	if (hash == core->hash && !strcmp(core->name, name))
 		return core;
 
 	hlist_for_each_entry(child, &core->children, child_node) {
-		ret = __clk_lookup_subtree(name, child);
+		ret = __clk_lookup_subtree(name, hash, child);
 		if (ret)
 			return ret;
 	}
@@ -313,20 +315,22 @@  static struct clk_core *clk_core_lookup(const char *name)
 {
 	struct clk_core *root_clk;
 	struct clk_core *ret;
+	unsigned int hash;
 
 	if (!name)
 		return NULL;
 
+	hash = full_name_hash(NULL, name, strlen(name));
 	/* search the 'proper' clk tree first */
 	hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
-		ret = __clk_lookup_subtree(name, root_clk);
+		ret = __clk_lookup_subtree(name, hash, root_clk);
 		if (ret)
 			return ret;
 	}
 
 	/* if not found, then search the orphan tree */
 	hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
-		ret = __clk_lookup_subtree(name, root_clk);
+		ret = __clk_lookup_subtree(name, hash, root_clk);
 		if (ret)
 			return ret;
 	}
@@ -3827,6 +3831,7 @@  __clk_register(struct device *dev, struct device_node *np, struct clk_hw *hw)
 		goto fail_name;
 	}
 
+	core->hash = full_name_hash(NULL, core->name, strlen(core->name));
 	if (WARN_ON(!init->ops)) {
 		ret = -EINVAL;
 		goto fail_ops;