On Thu, Jul 16, 2015 at 10:48 PM, Jens Axboe <ax...@kernel.dk> wrote: > On 07/15/2015 09:16 PM, Ming Lei wrote: >> >> Hi, >> >> This patches kills two kinds of atomic operations in block >> accounting I/O. >> >> The 1st two patches convert atomic refcount of partition >> into percpu refcount. >> >> The 2nd two patches converts partition->in_flight[] into percpu >> variable. >> >> With this change, ~15% throughput improvement can be observed >> when running fio(randread) over null blk in a dual-socket >> environment. > > > I've played with this before, but always ran into the hurdle of making > part_in_flight() too expensive ended up hurting results in the end. Making
Yes, it is a bit expensive, but it is only run at most one time per tick for one partition. > the inc/dec parts of accounting percpu is a no-brainer, unfortunately the > summing then becomes pretty expensive. I'll run this through some testing > and see what kind of results I get. The first two patches should be fine, and it still can get ~8% improvement in my test. > > -- > Jens Axboe > -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
