Commit Graph

3 Commits

Author SHA1 Message Date
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
Stafford Horne 266c7fad15 openrisc: Consolidate setup to use memblock instead of bootmem
Clearing out one todo item. Use the memblock boot time memory
which is the current standard.

Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Jonas <jonas@southpole.se>
Signed-off-by: Stafford Horne <shorne@gmail.com>
2016-12-12 23:10:00 +09:00
Jonas Bonn 616257669e OpenRISC: Miscellaneous
Adds README file, TODO list, and a couple of other pieces that didn't seem
to fit into any other patch.

Signed-off-by: Jonas Bonn <jonas@southpole.se>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
2011-07-22 18:46:41 +02:00