From: reg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Badhri Jagan Sridharan <badhri@google.com>
Cc: Guenter Roeck <linux@roeck-us.net>,
Heikki Krogerus <heikki.krogerus@linux.intel.com>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] usb: typec: tcpm: Move to high priority workqueue for processing events
Date: Tue, 14 Jul 2020 08:05:20 +0200 [thread overview]
Message-ID: <20200714060520.GB657428@kroah.com> (raw)
In-Reply-To: <20200713204300.345975-1-badhri@google.com>
On Mon, Jul 13, 2020 at 01:43:00PM -0700, Badhri Jagan Sridharan wrote:
> "tReceiverResponse 15 ms Section 6.6.2
> The receiver of a Message requiring a response Shall respond
> within tReceiverResponse in order to ensure that the
> sender’s SenderResponseTimer does not expire."
>
> When the cpu complex is busy running other lower priority
> work items, TCPM's work queue sometimes does not get scheduled
> on time to meet the above requirement from the spec.
> Elevating the TCPM's work queue to higher priority allows
> TCPM to meet tReceiverResponse in a busy system.
>
> Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
> ---
> drivers/usb/typec/tcpm/tcpm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 82b19ebd7838e0..088b6f1fa1ff89 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -4747,7 +4747,7 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
> mutex_init(&port->lock);
> mutex_init(&port->swap_lock);
>
> - port->wq = create_singlethread_workqueue(dev_name(dev));
> + port->wq = alloc_ordered_workqueue("%s", WQ_HIGHPRI, dev_name(dev));
How are you "guaranteeing" that this is really going to change anything
on a highly loaded machine?
Yes, it might make things better, but if you have a hard deadline like
this, you need to do things a bit differently to always ensure that you
meet it. I do not think this change is that fix, do you?
thanks,
greg k-h
next prev parent reply other threads:[~2020-07-14 6:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-13 20:43 [PATCH] usb: typec: tcpm: Move to high priority workqueue for processing events Badhri Jagan Sridharan
2020-07-14 6:05 ` reg Kroah-Hartman [this message]
2020-07-14 6:57 ` Guenter Roeck
2020-07-14 17:16 ` Badhri Jagan Sridharan
2020-07-23 6:20 ` Badhri Jagan Sridharan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200714060520.GB657428@kroah.com \
--to=gregkh@linuxfoundation.org \
--cc=badhri@google.com \
--cc=heikki.krogerus@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=linux@roeck-us.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).