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From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Markus Schneider-Pargmann <msp@baylibre.com>
Cc: Chandrasekar Ramakrishnan <rcsekar@samsung.com>,
	Wolfgang Grandegger <wg@grandegger.com>,
	linux-can@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Subject: Re: [PATCH 02/15] can: m_can: Wakeup net queue once tx was issued
Date: Wed, 14 Dec 2022 10:22:01 +0100	[thread overview]
Message-ID: <20221214092201.xpb3rnwp5rtvrpkr@pengutronix.de> (raw)
In-Reply-To: <20221214091820.geugui5ws3f7a5ng@pengutronix.de>

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On 14.12.2022 10:18:20, Marc Kleine-Budde wrote:
> On 14.12.2022 10:14:06, Markus Schneider-Pargmann wrote:
> > Hi Marc,
> > 
> > On Wed, Nov 30, 2022 at 06:21:00PM +0100, Marc Kleine-Budde wrote:
> > > On 16.11.2022 21:52:55, Markus Schneider-Pargmann wrote:
> > > > Currently the driver waits to wakeup the queue until the interrupt for
> > > > the transmit event is received and acknowledged. If we want to use the
> > > > hardware FIFO, this is too late.
> > > > 
> > > > Instead release the queue as soon as the transmit was transferred into
> > > > the hardware FIFO. We are then ready for the next transmit to be
> > > > transferred.
> > > 
> > > If you want to really speed up the TX path, remove the worker and use
> > > the spi_async() API from the xmit callback, see mcp251xfd_start_xmit().
> > > 
> > > Extra bonus if you implement xmit_more() and transfer more than 1 skb
> > > per SPI transfer.
> > 
> > Just a quick question here, I mplemented a xmit_more() call and I am
> > testing it right now, but it always returns false even under high
> > pressure. The device has a txqueuelen set to 1000. Do I need to turn
> > some other knob for this to work?
> 
> AFAIK you need BQL support: see 0084e298acfe ("can: mcp251xfd: add BQL support").
> 
> The etas_es58x driver implements xmit_more(), I added the Author Vincent
> on Cc.

Have a look at netdev_queue_set_dql_min_limit() in the etas driver.

Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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  reply	other threads:[~2022-12-14  9:22 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-16 20:52 [PATCH 00/15] can: m_can: Optimizations for tcan and peripheral chips Markus Schneider-Pargmann
2022-11-16 20:52 ` [PATCH 01/15] can: m_can: Eliminate double read of TXFQS in tx_handler Markus Schneider-Pargmann
2022-11-16 20:52 ` [PATCH 02/15] can: m_can: Wakeup net queue once tx was issued Markus Schneider-Pargmann
2022-11-30 17:21   ` Marc Kleine-Budde
2022-12-01  8:43     ` Markus Schneider-Pargmann
2022-12-01  9:16       ` Marc Kleine-Budde
2022-12-01 16:49         ` Markus Schneider-Pargmann
2022-12-02  9:16           ` Marc Kleine-Budde
2022-12-14  9:14     ` Markus Schneider-Pargmann
2022-12-14  9:18       ` Marc Kleine-Budde
2022-12-14  9:22         ` Marc Kleine-Budde [this message]
2022-12-14 10:15           ` Vincent MAILHOL
2022-12-14 10:35             ` Markus Schneider-Pargmann
2022-12-15  9:31               ` Markus Schneider-Pargmann
2022-12-16  4:40                 ` Vincent MAILHOL
2022-12-14 10:18           ` Markus Schneider-Pargmann
2022-12-02 13:53   ` Marc Kleine-Budde
2022-11-16 20:52 ` [PATCH 03/15] can: m_can: Cache tx putidx and transmits in flight Markus Schneider-Pargmann
2022-12-01 11:14   ` Marc Kleine-Budde
2022-12-02  8:37     ` Markus Schneider-Pargmann
2022-12-02 14:46       ` Marc Kleine-Budde
2022-12-13 17:13         ` Markus Schneider-Pargmann
2022-12-13 19:17           ` Marc Kleine-Budde
2022-12-14  8:32             ` Markus Schneider-Pargmann
2022-11-16 20:52 ` [PATCH 04/15] can: m_can: Use transmit event FIFO watermark level interrupt Markus Schneider-Pargmann
2022-11-30 17:17   ` Marc Kleine-Budde
2022-12-01  8:25     ` Markus Schneider-Pargmann
2022-12-01  9:05       ` Marc Kleine-Budde
2022-12-01 10:12         ` Markus Schneider-Pargmann
2022-12-01 11:00           ` Marc Kleine-Budde
2022-12-01 16:59             ` Markus Schneider-Pargmann
2022-12-02  9:23               ` Marc Kleine-Budde
2022-12-02  9:43                 ` Markus Schneider-Pargmann
2022-12-02 14:03                   ` Marc Kleine-Budde
2022-12-13 17:19               ` Markus Schneider-Pargmann
2022-12-13 19:18                 ` Marc Kleine-Budde
2022-11-16 20:52 ` [PATCH 05/15] can: m_can: Disable unused interrupts Markus Schneider-Pargmann
2022-11-16 20:52 ` [PATCH 06/15] can: m_can: Avoid reading irqstatus twice Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 07/15] can: m_can: Read register PSR only on error Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 08/15] can: m_can: Count TXE FIFO getidx in the driver Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 09/15] can: m_can: Count read getindex " Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 10/15] can: m_can: Batch acknowledge rx fifo Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 11/15] can: m_can: Batch acknowledge transmit events Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 12/15] can: tcan4x5x: Remove invalid write in clear_interrupts Markus Schneider-Pargmann
2022-12-02 14:17   ` Marc Kleine-Budde
2022-11-16 20:53 ` [PATCH 13/15] can: tcan4x5x: Fix use of register error status mask Markus Schneider-Pargmann
2022-12-02 14:19   ` Marc Kleine-Budde
2022-11-16 20:53 ` [PATCH 14/15] can: tcan4x5x: Fix register range of first block Markus Schneider-Pargmann
2022-12-02 14:28   ` Marc Kleine-Budde
2022-12-05  9:30     ` Markus Schneider-Pargmann
2022-12-05  9:44       ` Marc Kleine-Budde
2022-12-05  9:55         ` Markus Schneider-Pargmann
2022-11-16 20:53 ` [PATCH 15/15] can: tcan4x5x: Specify separate read/write ranges Markus Schneider-Pargmann
2022-12-02 14:03 ` [PATCH 00/15] can: m_can: Optimizations for tcan and peripheral chips Marc Kleine-Budde
2022-12-05  9:09   ` Markus Schneider-Pargmann

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