All of lore.kernel.org
 help / color / mirror / Atom feed
From: Stas Sergeev <stsp@list.ru>
To: Johan Hovold <jhovold@gmail.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
	Jarkko Huijts <jarkko.huijts@gmail.com>,
	Alan Cox <alan@linux.intel.com>,
	linux-usb@vger.kernel.org, linux-serial@vger.kernel.org,
	Linux kernel <linux-kernel@vger.kernel.org>,
	Caylan Van Larson <i@caylan.net>,
	"Rafael J. Wysocki" <rjw@sisk.pl>
Subject: Re: Regression: ftdi_sio is slow (since Wed Oct 10 15:05:06 2012)
Date: Sat, 04 May 2013 16:44:05 +0400	[thread overview]
Message-ID: <51850295.6020601@list.ru> (raw)
In-Reply-To: <20130504111535.GC16818@localhost>

04.05.2013 15:15, Johan Hovold пишет:
> The query takes longer than the transmit at decent baudrates (>=38k)
> and under the assumption that flow control isn't causing any delays.
>
> But you do have a point, and I have been meaning to look into whether
> the added overhead of checking the hardware buffers could be mitigated
> by adding wait_until_sent support to usb-serial. This way the we would
> only query the hardware buffers on tty_wait_until_sent (e.g. at close)
> and select and TIOCMOUTQ would not suffer. This is also the way things
> are handled in serial_core.
Thanks for taking a look.
Indeed, it seems .wait_until_sent is the best candidate for that
kind of things, and the patch in question would even match its
description be it using .wait_until_sent and not .chars_in_buffer.
Please count on testing your patches here when they are ready.
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

WARNING: multiple messages have this Message-ID (diff)
From: Stas Sergeev <stsp@list.ru>
To: Johan Hovold <jhovold@gmail.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
	Jarkko Huijts <jarkko.huijts@gmail.com>,
	Alan Cox <alan@linux.intel.com>,
	linux-usb@vger.kernel.org, linux-serial@vger.kernel.org,
	Linux kernel <linux-kernel@vger.kernel.org>,
	Caylan Van Larson <i@caylan.net>,
	"Rafael J. Wysocki" <rjw@sisk.pl>
Subject: Re: Regression: ftdi_sio is slow (since Wed Oct 10 15:05:06 2012)
Date: Sat, 04 May 2013 16:44:05 +0400	[thread overview]
Message-ID: <51850295.6020601@list.ru> (raw)
In-Reply-To: <20130504111535.GC16818@localhost>

04.05.2013 15:15, Johan Hovold пишет:
> The query takes longer than the transmit at decent baudrates (>=38k)
> and under the assumption that flow control isn't causing any delays.
>
> But you do have a point, and I have been meaning to look into whether
> the added overhead of checking the hardware buffers could be mitigated
> by adding wait_until_sent support to usb-serial. This way the we would
> only query the hardware buffers on tty_wait_until_sent (e.g. at close)
> and select and TIOCMOUTQ would not suffer. This is also the way things
> are handled in serial_core.
Thanks for taking a look.
Indeed, it seems .wait_until_sent is the best candidate for that
kind of things, and the patch in question would even match its
description be it using .wait_until_sent and not .chars_in_buffer.
Please count on testing your patches here when they are ready.

  parent reply	other threads:[~2013-05-04 11:46 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-03 15:02 Regression: ftdi_sio is slow (since Wed Oct 10 15:05:06 2012) Stas Sergeev
2013-05-03 16:30 ` Greg KH
2013-05-03 17:38   ` Stas Sergeev
2013-05-03 16:52     ` Greg KH
2013-05-03 18:05       ` Stas Sergeev
2013-05-03 17:16         ` Greg KH
2013-05-03 18:27           ` Stas Sergeev
2013-05-03 18:27             ` Stas Sergeev
2013-05-03 20:34             ` Greg KH
2013-05-03 20:34               ` Greg KH
     [not found]               ` <20130503203419.GA25932-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2013-05-03 21:50                 ` Stas Sergeev
2013-05-03 21:50                   ` Stas Sergeev
2013-05-04 11:15                   ` Johan Hovold
2013-05-04 11:15                     ` Johan Hovold
2013-05-04 11:39                     ` Peter Hurley
2013-05-05 18:29                       ` Johan Hovold
2013-05-05 18:32                         ` [PATCH 0/7] USB: serial: add wait_until_sent-support Johan Hovold
2013-05-05 18:32                           ` [PATCH 1/7] USB: serial: add wait_until_sent operation Johan Hovold
     [not found]                           ` <1367778753-22297-1-git-send-email-jhovold-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-05-05 18:32                             ` [PATCH 2/7] USB: serial: add generic wait_until_sent implementation Johan Hovold
2013-05-05 18:32                               ` Johan Hovold
2013-05-08 14:25                               ` Stas Sergeev
2013-05-08 14:25                                 ` Stas Sergeev
2013-05-08 15:48                                 ` Johan Hovold
2013-05-08 15:48                                   ` Johan Hovold
2013-05-08 15:51                               ` [PATCH v2 2/8] " Johan Hovold
2013-05-05 18:32                           ` [PATCH 3/7] USB: ftdi_sio: clean up get_modem_status Johan Hovold
2013-05-05 18:32                           ` [PATCH 4/7] USB: ftdi_sio: fix chars_in_buffer overhead Johan Hovold
2013-05-05 18:32                           ` [PATCH 5/7] USB: io_ti: " Johan Hovold
2013-05-05 18:32                           ` [PATCH 6/7] USB: ti_usb_3410_5052: " Johan Hovold
2013-05-05 18:32                           ` [PATCH 7/7] USB: serial: clean up chars_in_buffer Johan Hovold
     [not found]                           ` <81D166EE-BB85-4A72-A6FA-A1F6B5633CB0@caylan.net>
2013-05-20 10:07                             ` [PATCH 0/7] USB: serial: add wait_until_sent-support Johan Hovold
2013-05-04 12:44                     ` Stas Sergeev [this message]
2013-05-04 12:44                       ` Regression: ftdi_sio is slow (since Wed Oct 10 15:05:06 2012) Stas Sergeev
2013-05-04  9:37                 ` Stas Sergeev
2013-05-04  9:37                   ` Stas Sergeev
2013-05-03 18:15       ` Stas Sergeev

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=51850295.6020601@list.ru \
    --to=stsp@list.ru \
    --cc=alan@linux.intel.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=i@caylan.net \
    --cc=jarkko.huijts@gmail.com \
    --cc=jhovold@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-serial@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=rjw@sisk.pl \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.