mtip32xx: minor performance enhancements
authorSam Bradshaw <sbradshaw@micron.com>
Fri, 6 Jun 2014 19:28:48 +0000 (13:28 -0600)
committerJens Axboe <axboe@fb.com>
Fri, 6 Jun 2014 19:28:48 +0000 (13:28 -0600)
commitf45c40a92d2c6915a0e88ff8a947095be2ba1c8e
tree20ca1854aefee878ca5606b98cfdfe920f511b47
parentf6be4fb4bcb396fc3b1c134b7863351972de081f
mtip32xx: minor performance enhancements

This patch adds the following:

1) Compiler hinting in the fast path.
2) A prefetch of port->flags to eliminate moderate cpu stalling later
in mtip_hw_submit_io().
3) Eliminate a redundant rq_data_dir().
4) Reorder members of driver_data to eliminate false cacheline sharing
between irq_workers_active and unal_qdepth.

With some workload and topology configurations, I'm seeing ~1.5%
throughput improvement in small block random read benchmarks as well
as improved latency std. dev.

Signed-off-by: Sam Bradshaw <sbradshaw@micron.com>
Add include of <linux/prefetch.h>

Signed-off-by: Jens Axboe <axboe@fb.com>
drivers/block/mtip32xx/mtip32xx.c
drivers/block/mtip32xx/mtip32xx.h