Re: [PATCH net-next v2 3/4] virtio-net: auto-tune mergeable rx buffer size for improved performance

On Wed, Jan 08, 2014 at 07:41:58PM -0800, Michael Dalton wrote:

Sorry, forgot to mention - if we want to explore combining the buffer
address and truesize into a single void *, we could also exploit the
fact that our size ranges from aligned GOOD_PACKET_LEN to PAGE_SIZE, and
potentially encode fewer values for truesize (and require a smaller
alignment than 256). The prior e-mails discussion of 256 byte alignment
with 256 values is just one potential design point.

Best,

Mike

Good point. I think we should keep the option to
make buffers bigger than 4K, so I think we should start with 256
alignment, then see if there are workloads that are improved by smaller
alignment.

Can you add wrapper inline functions to pack/unpack size and
buffer pointer to/from void *?
This way it will be easy to experiment with different alignments.