From: Alexander Stein <alexander.stein@systec-electronic.com>
To: David Jander <david@protonic.nl>
Cc: "Marc Kleine-Budde" <mkl@pengutronix.de>,
linux-can@vger.kernel.org,
"Martin Däumler" <martin.daeumler@systec-electronic.com>,
"Daniel Krüger" <daniel.krueger@systec-electronic.com>
Subject: Re: [PATCH v2 00/12] can: rx-offload: add implmentation and switch flexcan driver to use it
Date: Wed, 05 Oct 2016 14:37:20 +0200 [thread overview]
Message-ID: <1506116.7yduGgf9eG@ws-stein> (raw)
In-Reply-To: <20161004143315.23423e56@erd980>
Hi David,
On Tuesday 04 October 2016 14:33:15, David Jander wrote:
> > In summary the non-RT case seems fine now, but I wonder what causes the
> > delays on RT to the CAN-IRQ-Thread which seem to be about 500us (bus time
> > of 6 4Byte CAN frames).
>
> Thanks for testing!
> Well, in -RT I guess anything with a higher priority than the CAN-IRQ can
> cause a delay... but since going from -rt13 to -rt14 improved the situation,
> this sounds like bugs in the -rt code. Are you running any code in
> SCHED_FIFO that you don't run in the non-RT case?
AFAIK no userspace process is put into SCHED_FIFO and only the priority of
CAN-IRQ-Thread is increased to 91. Userspace runs with unchanged priority. So
yes I guess there is still problem in -rt code.
> It's nevertheless very nice to see that for non-RT, you got from losing
> messages to not losing any message with this patchset, even on a lowly
> i.MX35 at 1Mbit/s! This proves that the patchset is certainly worth it.
I would expect the same from running with RT enabled, especially as the CAN-
IRQ-Thread has SCHED_FIFO wuth priority 91. There shouldn't be much code which
can delay that thread.
Best regards,
Alexander
next prev parent reply other threads:[~2016-10-05 12:37 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-04 18:32 [PATCH v2 00/12] can: rx-offload: add implmentation and switch flexcan driver to use it Marc Kleine-Budde
2016-07-04 18:32 ` [PATCH v2 01/12] can: rx-offload: Add support for HW fifo based irq offloading Marc Kleine-Budde
2016-07-04 18:32 ` [PATCH v2 02/12] can: rx-offload: Add support for timestamp " Marc Kleine-Budde
2016-07-04 18:49 ` Andri Yngvason
2016-07-04 20:59 ` Marc Kleine-Budde
2016-07-04 22:30 ` Marc Kleine-Budde
2016-07-05 11:58 ` Andri Yngvason
2016-07-05 12:40 ` Marc Kleine-Budde
2016-07-05 5:46 ` Alexander Stein
2016-07-05 6:19 ` Marc Kleine-Budde
2016-07-05 6:31 ` David Jander
2016-07-05 7:21 ` Marc Kleine-Budde
2016-07-04 18:32 ` [PATCH v2 03/12] can: flexcan: remove write-only member pdata of struct flexcan_priv Marc Kleine-Budde
2016-07-04 18:32 ` [PATCH v2 04/12] can: flexcan: make declaration of devtype_data const Marc Kleine-Budde
2016-07-04 18:32 ` [PATCH v2 05/12] can: flexcan: calculate default value for imask1 during runtime Marc Kleine-Budde
2016-07-04 18:32 ` [PATCH v2 06/12] can: flexcan: make TX mailbox selectable " Marc Kleine-Budde
2016-07-04 18:32 ` [PATCH v2 07/12] can: flexcan: make use of rx-offload's irq_offload_fifo Marc Kleine-Budde
2016-07-04 18:32 ` [PATCH v2 08/12] can: flexcan: add missing register definitions Marc Kleine-Budde
2016-07-04 18:32 ` [PATCH v2 09/12] can: flexcan: activate individual RX masking and initialize reg_rximr Marc Kleine-Budde
2016-07-04 18:32 ` [PATCH v2 10/12] can: flexcan: add quirk FLEXCAN_QUIRK_ENABLE_EACEN_RRS Marc Kleine-Budde
2016-07-04 18:32 ` [PATCH v2 11/12] can: flexcan: add support for timestamp based rx-offload Marc Kleine-Budde
2016-07-04 18:32 ` [PATCH v2 12/12] can: flexcan: switch imx6 and vf610 to timestamp based offloading Marc Kleine-Budde
2016-07-13 7:28 ` [PATCH v2 00/12] can: rx-offload: add implmentation and switch flexcan driver to use it Mirza Krak
2016-07-13 7:46 ` Marc Kleine-Budde
2016-09-07 6:33 ` Holger Schurig
2016-10-04 6:32 ` Holger Schurig
2016-10-04 11:57 ` Alexander Stein
2016-10-04 12:33 ` David Jander
2016-10-05 12:37 ` Alexander Stein [this message]
2016-11-30 14:22 ` Alexander Stein
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