From: Sujith <m.sujith@gmail.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Sujith <m.sujith@gmail.com>, Martin Schleier <drahemmaps@gmx.net>,
Jussi Kivilinna <jussi.kivilinna@mbnet.fi>,
<linux-wireless@vger.kernel.org>, <dsd@gentoo.org>,
<linville@tuxdriver.com>, <kune@deine-taler.de>,
<linux-usb@vger.kernel.org>, <gregkh@suse.de>
Subject: Re: Override endpoint attributes (was: RE: [PATCH] zd1211rw: change endpoint types of EP_REGS_OUT and EP_INT_IN from interrupt to bulk)
Date: Sun, 6 Feb 2011 21:45:31 +0530 [thread overview]
Message-ID: <19790.51491.583675.986658@gargle.gargle.HOWL> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1102061037060.20379-100000@netrider.rowland.org>
Alan Stern wrote:
> Why do you want to? Why does changing the endpoint type from interrupt
> to bulk improve performance? Yes, the description says that this
> causes CPU usage to go from 10% to below 1%, but _why_ does it do that?
>
> Maybe the same effect can be achieved simply by changing the interrupt
> interval instead.
Well, when the device is plugged in, the USB core recognizes the endpoints
as interrupt type. Later, in the probe() callback, the FW is uploaded to the
target and it patches the endpoints' type to bulk. Please correct me if am
wrong, but I think this mismatch between the host and the target would be
the cause for the high CPU usage, when the transmission load for that
endpoint is high.
Sujith
next prev parent reply other threads:[~2011-02-06 16:16 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-06 10:27 Override endpoint attributes (was: RE: [PATCH] zd1211rw: change endpoint types of EP_REGS_OUT and EP_INT_IN from interrupt to bulk) Martin Schleier
2011-02-06 11:33 ` Jussi Kivilinna
2011-02-06 12:07 ` Sujith
2011-02-06 15:46 ` Alan Stern
2011-02-06 16:15 ` Sujith [this message]
2011-02-06 20:04 ` Alan Stern
2011-02-08 12:03 ` Jussi Kivilinna
2011-02-08 15:21 ` Alan Stern
2011-02-08 19:08 ` Jussi Kivilinna
2011-02-09 2:28 ` Sujith
2011-02-09 15:19 ` Alan Stern
2011-02-09 16:30 ` Sujith
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=19790.51491.583675.986658@gargle.gargle.HOWL \
--to=m.sujith@gmail.com \
--cc=drahemmaps@gmx.net \
--cc=dsd@gentoo.org \
--cc=gregkh@suse.de \
--cc=jussi.kivilinna@mbnet.fi \
--cc=kune@deine-taler.de \
--cc=linux-usb@vger.kernel.org \
--cc=linux-wireless@vger.kernel.org \
--cc=linville@tuxdriver.com \
--cc=stern@rowland.harvard.edu \
/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