Re: [PATCH BUGFIX] block, bfq: stress that low_latency must be off to get max throughput

From: Jens Axboe
Date: Tue May 09 2017 - 10:54:37 EST


On 05/09/2017 04:54 AM, Paolo Valente wrote:
> The introduction of the BFQ and Kyber I/O schedulers has triggered a
> new wave of I/O benchmarks. Unfortunately, comments and discussions on
> these benchmarks confirm that there is still little awareness that it
> is very hard to achieve, at the same time, a low latency and a high
> throughput. In particular, virtually all benchmarks measure
> throughput, or throughput-related figures of merit, but, for BFQ, they
> use the scheduler in its default configuration. This configuration is
> geared, instead, toward a low latency. This is evidently a sign that
> BFQ documentation is still too unclear on this important aspect. This
> commit addresses this issue by stressing how BFQ configuration must be
> (easily) changed if the only goal is maximum throughput.

Added, thanks.

--
Jens Axboe