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From: Tony Lindgren <tony@atomide.com>
To: Matthieu CASTET <matthieu.castet@parrot.com>
Cc: Alan Stern <stern@rowland.harvard.edu>,
	Tom Mises <tommises@gmail.com>,
	linux-omap@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: High CPU usage when video streaming on EHCI, 3.17.8 kernel with DMA enabled
Date: Mon, 18 May 2015 07:59:20 -0700	[thread overview]
Message-ID: <20150518145919.GC10274@atomide.com> (raw)
In-Reply-To: <20150518102715.34e29c33@perruche.parrot.biz>

* Matthieu CASTET <matthieu.castet@parrot.com> [150518 01:34]:
> Hi,
> 
> last time I checked uvc driver, it was doing memcpy of video buffer : see uvc_video_decode_data.
> 
> It your video resolution is big, this can eat lot's of cpu.
> 
> Doing a trace should help you.

For the memcpy part with DMA this patch should help too:

[PATCH] dmaengine: omap-dma: Add support for memcpy

Regards,

Tony

  reply	other threads:[~2015-05-18 14:59 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-17  6:45 High CPU usage when video streaming on EHCI, 3.17.8 kernel with DMA enabled Tom Mises
     [not found] ` <CALmG-ASRge4g6euyUEaxrLryvNR_tFSRexFSDZ5HNuzx_W4AyA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-05-17 14:06   ` Alan Stern
2015-05-18  8:27     ` Matthieu CASTET
2015-05-18 14:59       ` Tony Lindgren [this message]
     [not found]         ` <20150518145919.GC10274-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
2015-05-21 21:20           ` Ash Charles
     [not found]             ` <CAK8F28mdedXgL660SqTLeNZ7hVHOmRR7YwuTdkyY3XmnZ97_Zw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-07-01 18:22               ` Tom Mises
     [not found]                 ` <CALmG-ARrzJ=kRH-958F20WPH+=VCpjrgMuyn9MWv4uj2dnSRpw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-07-02  6:22                   ` Tony Lindgren

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