linux-kernel - [RFC PATCH 3/4] refscale: Add benchmarks for percpu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240917143402.930114-4-boqun.feng@gmail.com>
Date: Tue, 17 Sep 2024 07:34:01 -0700
From: Boqun Feng <boqun.feng@...il.com>
To: linux-kernel@...r.kernel.org,
	rcu@...r.kernel.org,
	linux-mm@...ck.org,
	lkmm@...r.kernel.org
Cc: "Paul E. McKenney" <paulmck@...nel.org>,
	Frederic Weisbecker <frederic@...nel.org>,
	Neeraj Upadhyay <neeraj.upadhyay@...nel.org>,
	Joel Fernandes <joel@...lfernandes.org>,
	Josh Triplett <josh@...htriplett.org>,
	Boqun Feng <boqun.feng@...il.com>,
	Uladzislau Rezki <urezki@...il.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	Lai Jiangshan <jiangshanlai@...il.com>,
	Zqiang <qiang.zhang1211@...il.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Will Deacon <will@...nel.org>,
	Waiman Long <longman@...hat.com>,
	Mark Rutland <mark.rutland@....com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Kent Overstreet <kent.overstreet@...il.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Vlastimil Babka <vbabka@...e.cz>,
	maged.michael@...il.com
Subject: [RFC PATCH 3/4] refscale: Add benchmarks for percpu_ref

Benchmarks for percpu_ref are added to evaluate the reader side
performance between percpu_ref and other refcounting mechanisms.

Signed-off-by: Boqun Feng <boqun.feng@...il.com>
---
 kernel/rcu/refscale.c | 50 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 49 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c
index 7e76ae5159e6..97b73c980c5d 100644
--- a/kernel/rcu/refscale.c
+++ b/kernel/rcu/refscale.c
@@ -393,6 +393,54 @@ static struct ref_scale_ops hazptr_ops = {
 	.name		= "hazptr"
 };
 
+struct percpu_ref percpu_ref;
+
+static void percpu_ref_dummy(struct percpu_ref *ref) {}
+
+static bool percpu_ref_scale_init(void)
+{
+	int ret;
+
+	ret = percpu_ref_init(&percpu_ref, percpu_ref_dummy, PERCPU_REF_INIT_ATOMIC, GFP_KERNEL);
+	percpu_ref_switch_to_percpu(&percpu_ref);
+
+	return !ret;
+}
+
+static void percpu_ref_scale_cleanup(void)
+{
+	percpu_ref_exit(&percpu_ref);
+}
+
+static void percpu_ref_section(const int nloops)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		percpu_ref_get(&percpu_ref);
+		percpu_ref_put(&percpu_ref);
+	}
+}
+
+static void percpu_ref_delay_section(const int nloops, const int udl, const int ndl)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		percpu_ref_get(&percpu_ref);
+		un_delay(udl, ndl);
+		percpu_ref_put(&percpu_ref);
+	}
+}
+
+static struct ref_scale_ops percpu_ref_ops = {
+	.init		= percpu_ref_scale_init,
+	.cleanup	= percpu_ref_scale_cleanup,
+	.readsection	= percpu_ref_section,
+	.delaysection	= percpu_ref_delay_section,
+	.name		= "percpu_ref"
+};
+
 // Definitions for rwlock
 static rwlock_t test_rwlock;
 
@@ -1158,7 +1206,7 @@ ref_scale_init(void)
 	static struct ref_scale_ops *scale_ops[] = {
 		&rcu_ops, &srcu_ops, RCU_TRACE_OPS RCU_TASKS_OPS &refcnt_ops, &rwlock_ops,
 		&rwsem_ops, &lock_ops, &lock_irq_ops, &acqrel_ops, &clock_ops, &jiffies_ops,
-		&typesafe_ref_ops, &typesafe_lock_ops, &typesafe_seqlock_ops, &hazptr_ops,
+		&typesafe_ref_ops, &typesafe_lock_ops, &typesafe_seqlock_ops, &hazptr_ops, &percpu_ref_ops,
 	};
 
 	if (!torture_init_begin(scale_type, verbose))
-- 
2.45.2