diff mbox series

[iwl-next,v2] igc: Change Tx mode for MQPRIO offloading

Message ID 20250224-igc_mqprio_tx_mode-v2-1-9666da13c8d8@linutronix.de (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series [iwl-next,v2] igc: Change Tx mode for MQPRIO offloading | expand

Checks

Context Check Description
netdev/series_format warning Single patches do not need cover letters; Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 2 this patch: 2
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 121 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 29 this patch: 29
netdev/source_inline success Was 0 now: 0

Commit Message

Kurt Kanzenbach Feb. 24, 2025, 10:05 a.m. UTC 
The current MQPRIO offload implementation uses the legacy TSN Tx mode. In
this mode the hardware uses four packet buffers and considers queue
priorities.

In order to harmonize the TAPRIO implementation with MQPRIO, switch to the
regular TSN Tx mode. In addition to the legacy mode, transmission is always
coupled to Qbv. The driver already has mechanisms to use a dummy schedule
of 1 second with all gates open for ETF. Simply use this for MQPRIO too.

This reduces code and makes it easier to add support for frame preemption
later.

While at it limit the netdev_tc calls to MQPRIO only.

Tested on i225 with real time application using high priority queue, iperf3
using low priority queue and network TAP device.

Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
---
Changes in v2:
- Add comma to commit message (Faizal)
- Simplify if condition (Faizal)
- Link to v1: https://lore.kernel.org/r/20250217-igc_mqprio_tx_mode-v1-1-3a402fe1f326@linutronix.de
---
 drivers/net/ethernet/intel/igc/igc.h      |  4 +---
 drivers/net/ethernet/intel/igc/igc_main.c | 18 +++++++++++++-
 drivers/net/ethernet/intel/igc/igc_tsn.c  | 40 ++-----------------------------
 3 files changed, 20 insertions(+), 42 deletions(-)


---
base-commit: b66e19dcf684b21b6d3a1844807bd1df97ad197a
change-id: 20250214-igc_mqprio_tx_mode-22c19c564605

Best regards,

Comments

Loktionov, Aleksandr Feb. 24, 2025, 11:31 a.m. UTC | #1 
> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of
> Kurt Kanzenbach
> Sent: Monday, February 24, 2025 11:05 AM
> To: Nguyen, Anthony L <anthony.l.nguyen@intel.com>; Kitszel, Przemyslaw
> <przemyslaw.kitszel@intel.com>; Faizal Rahim
> <faizal.abdul.rahim@linux.intel.com>
> Cc: Andrew Lunn <andrew+netdev@lunn.ch>; David S. Miller
> <davem@davemloft.net>; Eric Dumazet <edumazet@google.com>; Jakub
> Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; Sebastian
> Andrzej Siewior <bigeasy@linutronix.de>; intel-wired-lan@lists.osuosl.org;
> netdev@vger.kernel.org; Kurt Kanzenbach <kurt@linutronix.de>
> Subject: [Intel-wired-lan] [PATCH iwl-next v2] igc: Change Tx mode for
> MQPRIO offloading
> 
> The current MQPRIO offload implementation uses the legacy TSN Tx mode. In
> this mode the hardware uses four packet buffers and considers queue
> priorities.
> 
> In order to harmonize the TAPRIO implementation with MQPRIO, switch to
> the regular TSN Tx mode. In addition to the legacy mode, transmission is
> always coupled to Qbv. The driver already has mechanisms to use a dummy
> schedule of 1 second with all gates open for ETF. Simply use this for MQPRIO
> too.
> 
> This reduces code and makes it easier to add support for frame preemption
> later.
> 
> While at it limit the netdev_tc calls to MQPRIO only.
> 
> Tested on i225 with real time application using high priority queue, iperf3
> using low priority queue and network TAP device.
> 
> Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
> ---
> Changes in v2:
> - Add comma to commit message (Faizal)
> - Simplify if condition (Faizal)
> - Link to v1: https://lore.kernel.org/r/20250217-igc_mqprio_tx_mode-v1-1-
> 3a402fe1f326@linutronix.de
> ---
>  drivers/net/ethernet/intel/igc/igc.h      |  4 +---
>  drivers/net/ethernet/intel/igc/igc_main.c | 18 +++++++++++++-
> drivers/net/ethernet/intel/igc/igc_tsn.c  | 40 ++-----------------------------
>  3 files changed, 20 insertions(+), 42 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/igc/igc.h
> b/drivers/net/ethernet/intel/igc/igc.h
> index
> cd1d7b6c1782352094f6867a31b6958c929bbbf4..16d85bdf55a7e9c412c4
> 7acf727bca6bc7154c61 100644
> --- a/drivers/net/ethernet/intel/igc/igc.h
> +++ b/drivers/net/ethernet/intel/igc/igc.h
> @@ -388,11 +388,9 @@ extern char igc_driver_name[];
>  #define IGC_FLAG_RX_LEGACY		BIT(16)
>  #define IGC_FLAG_TSN_QBV_ENABLED	BIT(17)
>  #define IGC_FLAG_TSN_QAV_ENABLED	BIT(18)
> -#define IGC_FLAG_TSN_LEGACY_ENABLED	BIT(19)
> 
>  #define IGC_FLAG_TSN_ANY_ENABLED				\
> -	(IGC_FLAG_TSN_QBV_ENABLED | IGC_FLAG_TSN_QAV_ENABLED |
> 	\
> -	 IGC_FLAG_TSN_LEGACY_ENABLED)
> +	(IGC_FLAG_TSN_QBV_ENABLED | IGC_FLAG_TSN_QAV_ENABLED)
> 
>  #define IGC_FLAG_RSS_FIELD_IPV4_UDP	BIT(6)
>  #define IGC_FLAG_RSS_FIELD_IPV6_UDP	BIT(7)
> diff --git a/drivers/net/ethernet/intel/igc/igc_main.c
> b/drivers/net/ethernet/intel/igc/igc_main.c
> index
> 3044392e8ded8619434040b9ccaa6b1babdbf685..0f44b0a6c166ae8aa798
> 93ea87f706be5d94397c 100644
> --- a/drivers/net/ethernet/intel/igc/igc_main.c
> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
> @@ -6678,13 +6678,14 @@ static int igc_tsn_enable_mqprio(struct
> igc_adapter *adapter,
>  				 struct tc_mqprio_qopt_offload *mqprio)  {
>  	struct igc_hw *hw = &adapter->hw;
> -	int i;
> +	int err, i;
> 
>  	if (hw->mac.type != igc_i225)
>  		return -EOPNOTSUPP;
> 
>  	if (!mqprio->qopt.num_tc) {
>  		adapter->strict_priority_enable = false;
> +		netdev_reset_tc(adapter->netdev);
>  		goto apply;
>  	}
> 
> @@ -6715,6 +6716,21 @@ static int igc_tsn_enable_mqprio(struct
> igc_adapter *adapter,
>  	igc_save_mqprio_params(adapter, mqprio->qopt.num_tc,
>  			       mqprio->qopt.offset);
> 
> +	err = netdev_set_num_tc(adapter->netdev, adapter->num_tc);
> +	if (err)
> +		return err;
> +
> +	for (i = 0; i < adapter->num_tc; i++) {
> +		err = netdev_set_tc_queue(adapter->netdev, i, 1,
> +					  adapter->queue_per_tc[i]);
> +		if (err)
> +			return err;
> +	}
> +
> +	/* In case the card is configured with less than four queues. */
> +	for (; i < IGC_MAX_TX_QUEUES; i++)
> +		adapter->queue_per_tc[i] = i;
> +
>  	mqprio->qopt.hw = TC_MQPRIO_HW_OFFLOAD_TCS;
> 
>  apply:
> diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c
> b/drivers/net/ethernet/intel/igc/igc_tsn.c
> index
> 1e44374ca1ffbb86e9893266c590f318984ef574..7c28f3e7bb576f0e6a21c8
> 83e934ede4d53096f4 100644
> --- a/drivers/net/ethernet/intel/igc/igc_tsn.c
> +++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
> @@ -37,18 +37,13 @@ static unsigned int igc_tsn_new_flags(struct
> igc_adapter *adapter)  {
>  	unsigned int new_flags = adapter->flags &
> ~IGC_FLAG_TSN_ANY_ENABLED;
> 
> -	if (adapter->taprio_offload_enable)
> -		new_flags |= IGC_FLAG_TSN_QBV_ENABLED;
> -
> -	if (is_any_launchtime(adapter))
> +	if (adapter->taprio_offload_enable || is_any_launchtime(adapter) ||
> +	    adapter->strict_priority_enable)
Isn't  sequence of:
if (adapter->taprio_offload_enable || adapter->strict_priority_enable || is_any_launchtime(adapter))
faster statistically?


>  		new_flags |= IGC_FLAG_TSN_QBV_ENABLED;
> 
>  	if (is_cbs_enabled(adapter))
>  		new_flags |= IGC_FLAG_TSN_QAV_ENABLED;
> 
> -	if (adapter->strict_priority_enable)
> -		new_flags |= IGC_FLAG_TSN_LEGACY_ENABLED;
> -
>  	return new_flags;
>  }
> 
> @@ -157,16 +152,12 @@ static int igc_tsn_disable_offload(struct
> igc_adapter *adapter)
>  	wr32(IGC_QBVCYCLET_S, 0);
>  	wr32(IGC_QBVCYCLET, NSEC_PER_SEC);
> 
> -	/* Reset mqprio TC configuration. */
> -	netdev_reset_tc(adapter->netdev);
> -
>  	/* Restore the default Tx arbitration: Priority 0 has the highest
>  	 * priority and is assigned to queue 0 and so on and so forth.
>  	 */
>  	igc_tsn_tx_arb(adapter, queue_per_tc);
> 
>  	adapter->flags &= ~IGC_FLAG_TSN_QBV_ENABLED;
> -	adapter->flags &= ~IGC_FLAG_TSN_LEGACY_ENABLED;
> 
>  	return 0;
>  }
> @@ -206,37 +197,10 @@ static int igc_tsn_enable_offload(struct igc_adapter
> *adapter)
>  		igc_tsn_set_retx_qbvfullthreshold(adapter);
> 
>  	if (adapter->strict_priority_enable) {
> -		int err;
> -
> -		err = netdev_set_num_tc(adapter->netdev, adapter-
> >num_tc);
> -		if (err)
> -			return err;
> -
> -		for (i = 0; i < adapter->num_tc; i++) {
> -			err = netdev_set_tc_queue(adapter->netdev, i, 1,
> -						  adapter->queue_per_tc[i]);
> -			if (err)
> -				return err;
> -		}
> -
> -		/* In case the card is configured with less than four queues. */
> -		for (; i < IGC_MAX_TX_QUEUES; i++)
> -			adapter->queue_per_tc[i] = i;
> -
>  		/* Configure queue priorities according to the user provided
>  		 * mapping.
>  		 */
>  		igc_tsn_tx_arb(adapter, adapter->queue_per_tc);
> -
> -		/* Enable legacy TSN mode which will do strict priority without
> -		 * any other TSN features.
> -		 */
> -		tqavctrl = rd32(IGC_TQAVCTRL);
> -		tqavctrl |= IGC_TQAVCTRL_TRANSMIT_MODE_TSN;
> -		tqavctrl &= ~IGC_TQAVCTRL_ENHANCED_QAV;
> -		wr32(IGC_TQAVCTRL, tqavctrl);
> -
> -		return 0;
>  	}
> 
>  	for (i = 0; i < adapter->num_tx_queues; i++) {
> 
> ---
> base-commit: b66e19dcf684b21b6d3a1844807bd1df97ad197a
> change-id: 20250214-igc_mqprio_tx_mode-22c19c564605
> 
> Best regards,
> --
> Kurt Kanzenbach
> Linutronix GmbH | Bahnhofstraße 3 | D-88690 Uhldingen-Mühlhofen
> Phone: +49 7556 25 999 27; Fax.: +49 7556 25 999 99
> 
> Hinweise zum Datenschutz finden Sie hier (Informations on data privacy can
> be found here): https://linutronix.de/legal/data-protection.php
> 
> Linutronix GmbH | Firmensitz (Registered Office): Uhldingen-Mühlhofen |
> Registergericht (Registration Court): Amtsgericht Freiburg i.Br., HRB700
> 806 | Geschäftsführer (Managing Directors): Heinz Egger, Thomas Gleixner
> Tiffany Silva, Sean Fennelly, Jeffrey Schneiderman
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h
index cd1d7b6c1782352094f6867a31b6958c929bbbf4..16d85bdf55a7e9c412c47acf727bca6bc7154c61 100644
--- a/drivers/net/ethernet/intel/igc/igc.h
+++ b/drivers/net/ethernet/intel/igc/igc.h
@@ -388,11 +388,9 @@  extern char igc_driver_name[];
 #define IGC_FLAG_RX_LEGACY		BIT(16)
 #define IGC_FLAG_TSN_QBV_ENABLED	BIT(17)
 #define IGC_FLAG_TSN_QAV_ENABLED	BIT(18)
-#define IGC_FLAG_TSN_LEGACY_ENABLED	BIT(19)
 
 #define IGC_FLAG_TSN_ANY_ENABLED				\
-	(IGC_FLAG_TSN_QBV_ENABLED | IGC_FLAG_TSN_QAV_ENABLED |	\
-	 IGC_FLAG_TSN_LEGACY_ENABLED)
+	(IGC_FLAG_TSN_QBV_ENABLED | IGC_FLAG_TSN_QAV_ENABLED)
 
 #define IGC_FLAG_RSS_FIELD_IPV4_UDP	BIT(6)
 #define IGC_FLAG_RSS_FIELD_IPV6_UDP	BIT(7)
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 3044392e8ded8619434040b9ccaa6b1babdbf685..0f44b0a6c166ae8aa79893ea87f706be5d94397c 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -6678,13 +6678,14 @@  static int igc_tsn_enable_mqprio(struct igc_adapter *adapter,
 				 struct tc_mqprio_qopt_offload *mqprio)
 {
 	struct igc_hw *hw = &adapter->hw;
-	int i;
+	int err, i;
 
 	if (hw->mac.type != igc_i225)
 		return -EOPNOTSUPP;
 
 	if (!mqprio->qopt.num_tc) {
 		adapter->strict_priority_enable = false;
+		netdev_reset_tc(adapter->netdev);
 		goto apply;
 	}
 
@@ -6715,6 +6716,21 @@  static int igc_tsn_enable_mqprio(struct igc_adapter *adapter,
 	igc_save_mqprio_params(adapter, mqprio->qopt.num_tc,
 			       mqprio->qopt.offset);
 
+	err = netdev_set_num_tc(adapter->netdev, adapter->num_tc);
+	if (err)
+		return err;
+
+	for (i = 0; i < adapter->num_tc; i++) {
+		err = netdev_set_tc_queue(adapter->netdev, i, 1,
+					  adapter->queue_per_tc[i]);
+		if (err)
+			return err;
+	}
+
+	/* In case the card is configured with less than four queues. */
+	for (; i < IGC_MAX_TX_QUEUES; i++)
+		adapter->queue_per_tc[i] = i;
+
 	mqprio->qopt.hw = TC_MQPRIO_HW_OFFLOAD_TCS;
 
 apply:
diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c
index 1e44374ca1ffbb86e9893266c590f318984ef574..7c28f3e7bb576f0e6a21c883e934ede4d53096f4 100644
--- a/drivers/net/ethernet/intel/igc/igc_tsn.c
+++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
@@ -37,18 +37,13 @@  static unsigned int igc_tsn_new_flags(struct igc_adapter *adapter)
 {
 	unsigned int new_flags = adapter->flags & ~IGC_FLAG_TSN_ANY_ENABLED;
 
-	if (adapter->taprio_offload_enable)
-		new_flags |= IGC_FLAG_TSN_QBV_ENABLED;
-
-	if (is_any_launchtime(adapter))
+	if (adapter->taprio_offload_enable || is_any_launchtime(adapter) ||
+	    adapter->strict_priority_enable)
 		new_flags |= IGC_FLAG_TSN_QBV_ENABLED;
 
 	if (is_cbs_enabled(adapter))
 		new_flags |= IGC_FLAG_TSN_QAV_ENABLED;
 
-	if (adapter->strict_priority_enable)
-		new_flags |= IGC_FLAG_TSN_LEGACY_ENABLED;
-
 	return new_flags;
 }
 
@@ -157,16 +152,12 @@  static int igc_tsn_disable_offload(struct igc_adapter *adapter)
 	wr32(IGC_QBVCYCLET_S, 0);
 	wr32(IGC_QBVCYCLET, NSEC_PER_SEC);
 
-	/* Reset mqprio TC configuration. */
-	netdev_reset_tc(adapter->netdev);
-
 	/* Restore the default Tx arbitration: Priority 0 has the highest
 	 * priority and is assigned to queue 0 and so on and so forth.
 	 */
 	igc_tsn_tx_arb(adapter, queue_per_tc);
 
 	adapter->flags &= ~IGC_FLAG_TSN_QBV_ENABLED;
-	adapter->flags &= ~IGC_FLAG_TSN_LEGACY_ENABLED;
 
 	return 0;
 }
@@ -206,37 +197,10 @@  static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 		igc_tsn_set_retx_qbvfullthreshold(adapter);
 
 	if (adapter->strict_priority_enable) {
-		int err;
-
-		err = netdev_set_num_tc(adapter->netdev, adapter->num_tc);
-		if (err)
-			return err;
-
-		for (i = 0; i < adapter->num_tc; i++) {
-			err = netdev_set_tc_queue(adapter->netdev, i, 1,
-						  adapter->queue_per_tc[i]);
-			if (err)
-				return err;
-		}
-
-		/* In case the card is configured with less than four queues. */
-		for (; i < IGC_MAX_TX_QUEUES; i++)
-			adapter->queue_per_tc[i] = i;
-
 		/* Configure queue priorities according to the user provided
 		 * mapping.
 		 */
 		igc_tsn_tx_arb(adapter, adapter->queue_per_tc);
-
-		/* Enable legacy TSN mode which will do strict priority without
-		 * any other TSN features.
-		 */
-		tqavctrl = rd32(IGC_TQAVCTRL);
-		tqavctrl |= IGC_TQAVCTRL_TRANSMIT_MODE_TSN;
-		tqavctrl &= ~IGC_TQAVCTRL_ENHANCED_QAV;
-		wr32(IGC_TQAVCTRL, tqavctrl);
-
-		return 0;
 	}
 
 	for (i = 0; i < adapter->num_tx_queues; i++) {