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From:   Baolin Wang <baolin.wang@linaro.org>
Date:   Mon, 9 Sep 2019 20:16:43 +0800
Message-ID: <CAMz4kuKsk7ZN2BnD4zp53PQE22jD-BTsJLL53SL3ndZ5=OCHYA@mail.gmail.com>
Subject: Re: [PATCH 2/4] mmc: Add virtual command queue support
To:     Adrian Hunter <adrian.hunter@intel.com>
Cc:     Ulf Hansson <ulf.hansson@linaro.org>, riteshh@codeaurora.org,
        asutoshd@codeaurora.org, Orson Zhai <orsonzhai@gmail.com>,
        Chunyan Zhang <zhang.lyra@gmail.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Linus Walleij <linus.walleij@linaro.org>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        linux-mmc <linux-mmc@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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Hi Adrian,

On Mon, 9 Sep 2019 at 20:02, Adrian Hunter <adrian.hunter@intel.com> wrote:
>
> On 6/09/19 6:52 AM, Baolin Wang wrote:
> > Now the MMC read/write stack will always wait for previous request is
> > completed by mmc_blk_rw_wait(), before sending a new request to hardware,
> > or queue a work to complete request, that will bring context switching
> > overhead, especially for high I/O per second rates, to affect the IO
> > performance.
> >
> > Thus this patch introduces virtual command queue interface, which is
> > similar with the hardware command queue engine's idea, that can remove
> > the context switching.
>
> CQHCI is a hardware interface for eMMC's that support command queuing.  What
> you are doing is a software issue queue, unrelated to CQHCI.  I think you

Yes.

> should avoid all reference to CQHCI i.e. call it something else.

Since its process is similar with CQHCI and re-use the CQHCI's
interfaces, I called it virtual command queue. I am not sure what else
name is better, any thoughts? VCQHCI? Thanks.

--
Baolin Wang
Best Regards