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Re: [Qemu-devel] [RFC 1/2] pci-dma-api-v1
From: |
Blue Swirl |
Subject: |
Re: [Qemu-devel] [RFC 1/2] pci-dma-api-v1 |
Date: |
Fri, 28 Nov 2008 21:03:06 +0200 |
On 11/28/08, Andrea Arcangeli <address@hidden> wrote:
> On Fri, Nov 28, 2008 at 07:59:13PM +0200, Blue Swirl wrote:
> > I don't know, here's a pointer:
> > http://lists.gnu.org/archive/html/qemu-devel/2008-08/msg00092.html
>
>
> I'm in total agreement with it. The missing "proper vectored AIO
> operations" are bdrv_aio_readv/writev ;).
>
> I wonder how can possibly aio_readv/writev be missing in posix aio?
> Unbelievable. It'd be totally trivial to add those to glibc, much
> easier infact than to pthread_create by hand, but how can we add a
> dependency on a certain glibc version? Ironically it'll be more
> user-friendly to add dependency on linux kernel-aio implementation
> that is already available for ages and it's guaranteed to run faster
> (or at least not slower).
There's also lio_listio that provides for vectored AIO.
> > Sorry, my description seems to have lead you to a totally wrong track.
> > I meant this scenario: device (Lance Ethernet) -> DMA controller
> > (MACIO) -> IOMMU -> physical memory. (In this case vectored DMA won't
> > be useful since there is byte swapping involved, but serves as an
> > example about generic DMA). At each step the DMA address is rewritten.
> > It would be nice if the interface between Lance and DMA, DMA and IOMMU
> > and IOMMU and memory was the same.
>
>
> No problem. So you think I should change it to qemu_dma_sg instead of
> pci_dma_sg? We can decide it later, but surely we can think about it
> in the meantime ;).
Yes.
> > Here's some history, please have a look.
> >
> > My first failed attempt:
> > http://lists.gnu.org/archive/html/qemu-devel/2007-08/msg00179.html
> >
> > My second failed rough sketch:
> > http://lists.gnu.org/archive/html/qemu-devel/2007-10/msg00626.html
> >
> > Anthony's version:
> > http://lists.gnu.org/archive/html/qemu-devel/2008-03/msg00474.html
> >
> > Anthony's second version:
> > http://lists.gnu.org/archive/html/qemu-devel/2008-04/msg00077.html
>
>
> Thanks a lot for the pointers.
Perhaps you could point out why the previous attempts failed, but
yours won't? ;-)
- [Qemu-devel] [RFC 1/2] pci-dma-api-v1, Andrea Arcangeli, 2008/11/27
- [Qemu-devel] [RFC 2/2] bdrv_aio_readv/writev_em, Andrea Arcangeli, 2008/11/27
- Re: [Qemu-devel] [RFC 1/2] pci-dma-api-v1, Blue Swirl, 2008/11/27
- Re: [Qemu-devel] [RFC 1/2] pci-dma-api-v1, Andrea Arcangeli, 2008/11/27
- Re: [Qemu-devel] [RFC 1/2] pci-dma-api-v1, Blue Swirl, 2008/11/28
- Re: [Qemu-devel] [RFC 1/2] pci-dma-api-v1, Andrea Arcangeli, 2008/11/28
- Re: [Qemu-devel] [RFC 1/2] pci-dma-api-v1,
Blue Swirl <=
- Re: [Qemu-devel] [RFC 1/2] pci-dma-api-v1, Jamie Lokier, 2008/11/28
- Re: [Qemu-devel] [RFC 1/2] pci-dma-api-v1, Avi Kivity, 2008/11/29
- Re: [Qemu-devel] [RFC 1/2] pci-dma-api-v1, Andrea Arcangeli, 2008/11/30
- Re: [Qemu-devel] [RFC 1/2] pci-dma-api-v1, Anthony Liguori, 2008/11/30
- Re: [Qemu-devel] [RFC 1/2] pci-dma-api-v1, Andrea Arcangeli, 2008/11/30
- [Qemu-devel] [RFC 1/1] pci-dma-api-v2, Andrea Arcangeli, 2008/11/30
- [Qemu-devel] Re: [RFC 1/1] pci-dma-api-v2, Blue Swirl, 2008/11/30
- [Qemu-devel] Re: [RFC 1/1] pci-dma-api-v2, Andrea Arcangeli, 2008/11/30
- [Qemu-devel] Re: [RFC 1/1] pci-dma-api-v2, Blue Swirl, 2008/11/30
- [Qemu-devel] Re: [RFC 1/1] pci-dma-api-v2, Andrea Arcangeli, 2008/11/30