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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: "Tomasz Moń" <tomasz.mon@camlingroup.com>
Cc: linux-serial@vger.kernel.org, Jiri Slaby <jirislaby@kernel.org>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	k.drobinski@camlintechnologies.com
Subject: Re: [PATCH] serial: imx: reduce RX interrupt frequency
Date: Tue, 4 Jan 2022 11:54:47 +0100	[thread overview]
Message-ID: <YdQndwYc9xaauvpS@kroah.com> (raw)
In-Reply-To: <20220104103203.2033673-1-tomasz.mon@camlingroup.com>

On Tue, Jan 04, 2022 at 11:32:03AM +0100, Tomasz Moń wrote:
> Triggering RX interrupt for every byte defeats the purpose of aging
> timer and leads to interrupt starvation at high baud rates.
> 
> Increase receiver trigger level to 8 to increase the minimum period
> between RX interrupts to 8 characters time. The tradeoff is increased
> latency. In the worst case scenario, where RX data has intercharacter
> delay slightly less than aging timer (8 characters time), it can take
> up to 63 characters time for the interrupt to be raised since the
> reception of the first character.

Why can't you do this dynamically based on the baud rate so as to always
work properly for all speeds without increased delays for slower ones?

thanks,

greg k-h

  parent reply	other threads:[~2022-01-04 10:54 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-04 10:32 [PATCH] serial: imx: reduce RX interrupt frequency Tomasz Moń
2022-01-04 10:43 ` Ahmad Fatoum
2022-01-04 11:05   ` Tomasz Moń
2022-01-04 10:54 ` Greg Kroah-Hartman [this message]
2022-01-04 11:13   ` Tomasz Moń
2022-01-04 11:38     ` Greg Kroah-Hartman
2022-01-04 22:49       ` Uwe Kleine-König
2022-01-05  7:59         ` Tomasz Moń
2022-01-05 10:37           ` Greg Kroah-Hartman
2022-01-05 10:56             ` Tomasz Moń
2022-01-05 10:57             ` Marc Kleine-Budde
2022-01-06 15:39               ` Sergey Organov
2022-01-05 13:34         ` Sergey Organov
2022-01-06 15:05           ` Uwe Kleine-König
2022-01-10  6:14             ` Tomasz Moń
2022-01-10  8:31               ` Uwe Kleine-König
2022-01-05 13:00   ` Sergey Organov
2022-01-05 13:04     ` Marc Kleine-Budde
2022-01-05 13:37       ` Sergey Organov
2022-01-05 13:40         ` Marc Kleine-Budde
2022-01-05 14:37           ` Sergey Organov

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