linux/arch/openrisc/TODO.openrisc
Stafford Horne f5d45dc911 openrisc: Add optimized memcpy routine
The generic memcpy routine provided in kernel does only byte copies.
Using word copies we can lower boot time and cycles spend in memcpy
quite significantly.

Booting on my de0 nano I see boot times go from 7.2 to 5.6 seconds.
The avg cycles in memcpy during boot go from 6467 to 1887.

I tested several algorithms (see code in previous patch mails)

The implementations I tested and avg cycles:
  - Word Copies + Loop Unrolls + Non Aligned    1882
  - Word Copies + Loop Unrolls                  1887
  - Word Copies                                 2441
  - Byte Copies + Loop Unrolls                  6467
  - Byte Copies                                 7600

In the end I ended up going with Word Copies + Loop Unrolls as it
provides best tradeoff between simplicity and boot speedups.

Signed-off-by: Stafford Horne <shorne@gmail.com>
2017-02-25 04:14:36 +09:00

13 lines
611 B
Plaintext

The OpenRISC Linux port is fully functional and has been tracking upstream
since 2.6.35. There are, however, remaining items to be completed within
the coming months. Here's a list of known-to-be-less-than-stellar items
that are due for investigation shortly, i.e. our TODO list:
-- Implement the rest of the DMA API... dma_map_sg, etc.
-- Finish the renaming cleanup... there are references to or32 in the code
which was an older name for the architecture. The name we've settled on is
or1k and this change is slowly trickling through the stack. For the time
being, or32 is equivalent to or1k.