linux-kernel - Re: [PATCH v2] Add support for usbfs zerocopy.

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Message-ID: <20160109105717.GB23584@imap.gmail.com>
Date:	Sat, 9 Jan 2016 11:57:21 +0100
From:	"Steinar H. Gunderson" <sesse@...gle.com>
To:	Lingzhu Xiang <lingzhu.xiang@...l.utoronto.ca>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	Alan Stern <stern@...land.harvard.edu>
Subject: Re: [PATCH v2] Add support for usbfs zerocopy.

On Fri, Jan 08, 2016 at 11:00:54PM -0500, Lingzhu Xiang wrote:
> Extended testing over one hour shows significant improved CPU usage
> and stability:
> The old CPU usage is about 12% +/- 5%. The new CPU usage is 4% +/- 1%.
> 
> The setup is an i7-4600U laptop running Kinect v2 with 260MB/s
> isochronous and 20MB/s bulk transfers.
> 
> The improvement in reducing jitter is particularly preferable to
> Kinect v2 driver because the isochronous data is structured and one
> packet lost means discarding a lot of data.

Thanks for testing this! It's not unexpected, but it's good to see others
are also seeing performance improvements.

/* Steinar */
-- 
Software Engineer, Google Switzerland