Hello, I am writing to the list to gauge interest for a modification of the md driver that allows it to take advantage of raid acceleration hardware. I/O processors like the Intel IOP333 (http://www.intel.com/design/iio/docs/iop333.htm) contain an xor engine for raid5 and raid6 calculations, but currently the md driver does not fully utilize these resources. Dave Jiang wrote a driver that re-routed calls to xor_block() to use the hardware xor engine. However, from my understating, he found that performance did not improve, due to the fact that md deals in PAGE_SIZE (4K) blocks. At 4K the overhead of setting up the engine destroys any performance advantage over a software xor. The goal of the modification would be to enable md to understand the capacity of the platform's xor resources and allow it to issue optimal block sizes. The first question is whether a solution along these lines would be valued by the community? The effort is non-trivial. Assuming a positive response I will solicit implementation ideas and acceptance criteria from the list. Thank you for your consideration, Dan - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
