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    SubjectRe: [PATCH 5/5] virtio-blk: implement ->make_request
    On Thu, Oct 06, 2011 at 12:22:14PM +1030, Rusty Russell wrote:
    > On Wed, 05 Oct 2011 15:54:08 -0400, Christoph Hellwig <> wrote:
    > > Add an alternate I/O path that implements ->make_request for virtio-blk.
    > > This is required for high IOPs devices which get slowed down to 1/5th of
    > > the native speed by all the locking, memory allocation and other overhead
    > > in the request based I/O path.
    > Ouch.
    > I'd be tempted to just switch across to this, though I'd be interested
    > to see if the simple add_buf change I referred to before has some effect
    > by itself (I doubt it).

    Benchmarking this more extensively even on low-end devices is number
    on my todo list after sorting out the virtqueue race and implementing
    flush/fua support. I'd really prefer to switch over to it
    unconditionally if the performance numbers allow it.

    > Also, though it's overkill I'd use standard list primitives rather than
    > open-coding a single linked list.

    I really prefer using standard helpers, but using a doubly linked list
    and increasing memory usage seems like such a waste. Maybe I should
    annoy Linus by proposing another iteration of a common single linked
    list implementation :)

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      Last update: 2011-10-06 15:45    [W:0.019 / U:14.364 seconds]
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