From nobody Sun Oct 5 09:10:54 2025 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.5]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7B223273FE; Wed, 6 Aug 2025 05:52:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.5 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754459572; cv=none; b=Ux++VAL63iSVPafK8T0ZDLsDYWW88oayZXbBZDjDVrmUPS9HO+z8EFWaLeCQuhnhKyAlXWSN9OCllDebHRlX3otHBHdxTBa6BwUWa/d8umP/81+C6DUB9Kbz33lWMKD8tzmwoQs821RdMqnbEVQ46s7a9vFyyTKqsATtQ+BmdVc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754459572; c=relaxed/simple; bh=YSRcS+dgRhVhp4dFl1VEUiNmKk0BAkoubIC6cIWnVo8=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=PtobHYqihRFJiM0o4DjaZxpqMHhQLvC9fVpfbDe6/at6lBxOg+ZKnIomI4vLQnGxbP7a8ZTK8BDjqzTAzYrGTXwJatEQsOljkpLuhgv0WpKik1au5LPojlW9wR/8HHm/tGTOMl2EhbWI5B+C6yi6ogapab/CpKwl+zgOhKFzaHw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=EPY7Sshd; arc=none smtp.client-ip=117.135.210.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="EPY7Sshd" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=Ao iFMQ50QbQOJteD++Wvjhr3mOpBX4MMEoWbs5t9s3E=; b=EPY7Sshd9Aoc3wQ2CA bZLW/b6cGYHa7dBHecWaF5cOiDBasmK/u4V6O4pkRDX474r5/8s3vZzKoB+ue1gU Mjx5lShT2kAGudx/26sZNuh9smHuMDP32XYVT3A0LvnmZiKlDd90cSxNoafdVb1D 97FDzy5vGJ1+Dr2e+ZmRvV2j4= Received: from zhaoxin-MS-7E12.. (unknown []) by gzga-smtp-mtada-g1-1 (Coremail) with SMTP id _____wD3f36N7ZJoRYI3AA--.9978S2; Wed, 06 Aug 2025 13:52:14 +0800 (CST) From: Xin Zhao To: willemdebruijn.kernel@gmail.com Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Xin Zhao Subject: [PATCH] net: af_packet: add af_packet hrtimer mode Date: Wed, 6 Aug 2025 13:52:10 +0800 Message-Id: <20250806055210.1530081-1-jackzxcui1989@163.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wD3f36N7ZJoRYI3AA--.9978S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxKF1fAF17ZFy5WFykCr15urg_yoW7Zw45pa y5GryxGw43J3Wagw4xJrn7AFyagwn5Ary5W393Xw1Sy3Z3try5t3Wj9F909FWfJFZrJ3y7 Ar4vqF15Cr1DX37anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0piiSdfUUUUU= X-CM-SenderInfo: pmdfy650fxxiqzyzqiywtou0bp/1tbiRxyhCmiS5LpRoQABsl Content-Type: text/plain; charset="utf-8" In a system with high real-time requirements, the timeout mechanism of ordinary timers with jiffies granularity is insufficient to meet the demands for real-time performance. Meanwhile, the optimization of CPU usage with af_packet is quite significant. Add hrtimer mode to help compensate for the shortcomings in real-time performance. Signed-off-by: Xin Zhao --- net/packet/Kconfig | 10 ++++++++++ net/packet/af_packet.c | 39 +++++++++++++++++++++++++++++++++++++++ net/packet/internal.h | 8 ++++++++ 3 files changed, 57 insertions(+) diff --git a/net/packet/Kconfig b/net/packet/Kconfig index 2997382d5..5e77ce08e 100644 --- a/net/packet/Kconfig +++ b/net/packet/Kconfig @@ -23,3 +23,13 @@ config PACKET_DIAG help Support for PF_PACKET sockets monitoring interface used by the ss tool. If unsure, say Y. + +config PACKET_HRTIMER + tristate "Packet: use hrtimer instead of timer" + depends on PACKET + default n + help + Support hrtimer mode for PF_PACKET sockets to improve real-time + performance. The default timeout mechanism with jiffies granularity + is insufficient to meet the demands for real-time performance. + If unsure, say N. diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index bc438d0d9..5c7e4ef89 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -203,7 +203,11 @@ static void prb_retire_current_block(struct tpacket_kb= dq_core *, static int prb_queue_frozen(struct tpacket_kbdq_core *); static void prb_open_block(struct tpacket_kbdq_core *, struct tpacket_block_desc *); +#ifdef CONFIG_PACKET_HRTIMER +static enum hrtimer_restart prb_retire_rx_blk_timer_expired(struct hrtimer= *); +#else static void prb_retire_rx_blk_timer_expired(struct timer_list *); +#endif static void _prb_refresh_rx_retire_blk_timer(struct tpacket_kbdq_core *); static void prb_fill_rxhash(struct tpacket_kbdq_core *, struct tpacket3_hd= r *); static void prb_clear_rxhash(struct tpacket_kbdq_core *, @@ -581,7 +585,11 @@ static __be16 vlan_get_protocol_dgram(const struct sk_= buff *skb) =20 static void prb_del_retire_blk_timer(struct tpacket_kbdq_core *pkc) { +#ifdef CONFIG_PACKET_HRTIMER + hrtimer_cancel(&pkc->retire_blk_timer); +#else timer_delete_sync(&pkc->retire_blk_timer); +#endif } =20 static void prb_shutdown_retire_blk_timer(struct packet_sock *po, @@ -603,9 +611,16 @@ static void prb_setup_retire_blk_timer(struct packet_s= ock *po) struct tpacket_kbdq_core *pkc; =20 pkc =3D GET_PBDQC_FROM_RB(&po->rx_ring); +#ifdef CONFIG_PACKET_HRTIMER + hrtimer_init(&pkc->retire_blk_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SO= FT); + pkc->retire_blk_timer.function =3D prb_retire_rx_blk_timer_expired; + if (pkc->tov_in_msecs =3D=3D 0) + pkc->tov_in_msecs =3D jiffies_to_msecs(1); +#else timer_setup(&pkc->retire_blk_timer, prb_retire_rx_blk_timer_expired, 0); pkc->retire_blk_timer.expires =3D jiffies; +#endif } =20 static int prb_calc_retire_blk_tmo(struct packet_sock *po, @@ -676,7 +691,11 @@ static void init_prb_bdqc(struct packet_sock *po, else p1->retire_blk_tov =3D prb_calc_retire_blk_tmo(po, req_u->req3.tp_block_size); +#ifdef CONFIG_PACKET_HRTIMER + p1->tov_in_msecs =3D p1->retire_blk_tov; +#else p1->tov_in_jiffies =3D msecs_to_jiffies(p1->retire_blk_tov); +#endif p1->blk_sizeof_priv =3D req_u->req3.tp_sizeof_priv; rwlock_init(&p1->blk_fill_in_prog_lock); =20 @@ -691,8 +710,15 @@ static void init_prb_bdqc(struct packet_sock *po, */ static void _prb_refresh_rx_retire_blk_timer(struct tpacket_kbdq_core *pkc) { +#ifdef CONFIG_PACKET_HRTIMER + hrtimer_start_range_ns(&pkc->retire_blk_timer, + ms_to_ktime(pkc->tov_in_msecs), + 0, + HRTIMER_MODE_REL_SOFT); +#else mod_timer(&pkc->retire_blk_timer, jiffies + pkc->tov_in_jiffies); +#endif pkc->last_kactive_blk_num =3D pkc->kactive_blk_num; } =20 @@ -719,8 +745,15 @@ static void _prb_refresh_rx_retire_blk_timer(struct tp= acket_kbdq_core *pkc) * prb_calc_retire_blk_tmo() calculates the tmo. * */ +#ifdef CONFIG_PACKET_HRTIMER +static enum hrtimer_restart prb_retire_rx_blk_timer_expired(struct hrtimer= *t) +#else static void prb_retire_rx_blk_timer_expired(struct timer_list *t) +#endif { +#ifdef CONFIG_PACKET_HRTIMER + enum hrtimer_restart ret =3D HRTIMER_RESTART; +#endif struct packet_sock *po =3D timer_container_of(po, t, rx_ring.prb_bdqc.retire_blk_timer); struct tpacket_kbdq_core *pkc =3D GET_PBDQC_FROM_RB(&po->rx_ring); @@ -787,9 +820,15 @@ static void prb_retire_rx_blk_timer_expired(struct tim= er_list *t) =20 refresh_timer: _prb_refresh_rx_retire_blk_timer(pkc); +#ifdef CONFIG_PACKET_HRTIMER + ret =3D HRTIMER_RESTART; +#endif =20 out: spin_unlock(&po->sk.sk_receive_queue.lock); +#ifdef CONFIG_PACKET_HRTIMER + return ret; +#endif } =20 static void prb_flush_block(struct tpacket_kbdq_core *pkc1, diff --git a/net/packet/internal.h b/net/packet/internal.h index 1e743d031..d9f2b2492 100644 --- a/net/packet/internal.h +++ b/net/packet/internal.h @@ -47,10 +47,18 @@ struct tpacket_kbdq_core { =20 unsigned short retire_blk_tov; unsigned short version; +#ifdef CONFIG_PACKET_HRTIMER + unsigned long tov_in_msecs; +#else unsigned long tov_in_jiffies; +#endif =20 /* timer to retire an outstanding block */ +#ifdef CONFIG_PACKET_HRTIMER + struct hrtimer retire_blk_timer; +#else struct timer_list retire_blk_timer; +#endif }; =20 struct pgv { --=20 2.34.1