Re: [PATCHSET v4] blk-mq-scheduling framework

From	Omar Sandoval <osandov@osandov.com>
Newsgroups	linux.kernel
Subject	Re: [PATCHSET v4] blk-mq-scheduling framework
Date	2016-12-22 18:20 +0100
Message-ID	<sRfc6-3Sa-15@gated-at.bofh.it> (permalink)
References	<sPaTf-2bJ-5@gated-at.bofh.it> <sReSK-3uM-29@gated-at.bofh.it> <sReSK-3uM-27@gated-at.bofh.it> <sRfc6-3Sa-17@gated-at.bofh.it>
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On Thu, Dec 22, 2016 at 04:57:36PM +0000, Bart Van Assche wrote:
> On Thu, 2016-12-22 at 08:52 -0800, Omar Sandoval wrote:
> > This approach occurred to us, but we couldn't figure out a way to make
> > blk_mq_tag_to_rq() work with it. From skimming over the patches, I
> > didn't see a solution to that problem.
> 
> Hello Omar,
> 
> Can you clarify your comment? Since my patches initialize both tags->rqs[]
> and sched_tags->rqs[] the function blk_mq_tag_to_rq() should still work.
> 
> Bart.

Sorry, you're right, it does work, but tags->rqs[] ends up being the
extra lookup table. I suspect that the runtime overhead of keeping that
up to date could be worse than copying the rq fields if you have lots of
CPUs but only one hardware queue.

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[PATCHSET v4] blk-mq-scheduling framework Jens Axboe <axboe@fb.com> - 2016-12-17 01:20 +0100
  [PATCH 2/8] blk-mq: make mq_ops a const pointer Jens Axboe <axboe@fb.com> - 2016-12-17 01:20 +0100
  Re: [PATCHSET v4] blk-mq-scheduling framework Paolo Valente <paolo.valente@linaro.org> - 2016-12-19 12:40 +0100
    Re: [PATCHSET v4] blk-mq-scheduling framework Paolo Valente <paolo.valente@linaro.org> - 2016-12-19 19:30 +0100
      Re: [PATCHSET v4] blk-mq-scheduling framework Paolo Valente <paolo.valente@linaro.org> - 2016-12-22 16:30 +0100
  Re: [PATCH 6/8] blk-mq-sched: add framework for MQ capable IO  schedulers Jens Axboe <axboe@fb.com> - 2016-12-21 03:30 +0100
    Re: [PATCH 6/8] blk-mq-sched: add framework for MQ capable IO schedulers Paolo Valente <paolo.valente@linaro.org> - 2016-12-22 16:30 +0100
  Re: [PATCH 6/8] blk-mq-sched: add framework for MQ capable IO schedulers Paolo Valente <paolo.valente@linaro.org> - 2016-12-22 11:00 +0100
    Re: [PATCH 6/8] blk-mq-sched: add framework for MQ capable IO schedulers Paolo Valente <paolo.valente@linaro.org> - 2016-12-22 12:20 +0100
    Re: [PATCH 6/8] blk-mq-sched: add framework for MQ capable IO schedulers Paolo Valente <paolo.valente@linaro.org> - 2016-12-23 11:20 +0100
  Re: [PATCHSET v4] blk-mq-scheduling framework Omar Sandoval <osandov@osandov.com> - 2016-12-22 18:00 +0100
    Re: [PATCHSET v4] blk-mq-scheduling framework Omar Sandoval <osandov@osandov.com> - 2016-12-22 18:20 +0100

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