Re: [PATCH v3 2/4] videobuf2-dma-streaming: new videobuf2 memoryallocator

From: Mauro Carvalho Chehab
Date: Mon Jan 07 2013 - 15:15:39 EST

Em Mon, 7 Jan 2013 12:40:50 -0700
Jonathan Corbet <corbet@xxxxxxx> escreveu:

> On Mon, 7 Jan 2013 00:09:47 +0100
> Alessandro Rubini <rubini@xxxxxxxxx> wrote:
> > I don't expect you'll see serious performance differences on the PC. I
> > think ARM users will have better benefits, due to the different cache
> > architecture. You told me Jon measured meaningful figures on a Marvel
> > CPU.
> It made the difference between 10 frames per second with the CPU running
> flat out and 30fps mostly idle. I think that probably counts as
> meaningful, yeah...:)

Couldn't this performance difference be due to the usage of GFP_DMA inside
the VB2 code, like Federico's new patch series is proposing?

If not, why are there a so large performance penalty?

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at