[PATCH 3/10] udlfb: pre-allocated urb list helpers

Greg KH greg at kroah.com
Thu Feb 18 15:54:56 UTC 2010

On Mon, Feb 15, 2010 at 06:45:55AM -0800, Bernie Thompson wrote:
> Add functions to pre-allocate and free usb bulk urbs for core render path.
> Udlfb currently allocates a single urb, guarded by a mutex, that is a key
> bottleneck. Because udlfb sends so much data, preallocation is most efficient.

I'm not going to reject this patch, but are you sure about this being
needed?  The code path for creating a new urb is very tiny, just a
memory allocation.  Is that really noticable in any benchmarks or cpu
usage that you have found?


greg k-h

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