Re: [PATCH] mtip32xx: minor performance enhancements

Jens Axboe
2014-06-06T18:55:58Z

On 06/06/2014 01:01 PM, Sam Bradshaw wrote:
> 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.

Seems I got a small bump in peak perf as well. In any case, it's
innocuous, so should do no harm to apply.

--
Jens Axboe