2023-09-14 18:48:55

by Ulf Hansson

Subject: Re: [PATCH V3 2/2] mmc: hsq: dynamic adjustment of hsq->depth

On Tue, 29 Aug 2023 at 04:05, Wenchao Chen <[email protected]> wrote:
>
> Increasing hsq_depth improves random write performance.
>
> Signed-off-by: Wenchao Chen <[email protected]>
> ---
> drivers/mmc/host/mmc_hsq.c | 27 +++++++++++++++++++++++++++
> drivers/mmc/host/mmc_hsq.h | 5 +++++
> 2 files changed, 32 insertions(+)
>
> diff --git a/drivers/mmc/host/mmc_hsq.c b/drivers/mmc/host/mmc_hsq.c
> index 8556cacb21a1..0984c39108ba 100644
> --- a/drivers/mmc/host/mmc_hsq.c
> +++ b/drivers/mmc/host/mmc_hsq.c
> @@ -21,6 +21,31 @@ static void mmc_hsq_retry_handler(struct work_struct *work)
> mmc->ops->request(mmc, hsq->mrq);
> }
>
> +static void mmc_hsq_modify_threshold(struct mmc_hsq *hsq)
> +{
> + struct mmc_host *mmc = hsq->mmc;
> + struct mmc_request *mrq;
> + struct hsq_slot *slot;
> + int need_change = 0;

Rather than using a variable to keep track of this, why not just do
the below here?

mmc->hsq_depth = HSQ_NORMAL_DEPTH;

> + int tag;
> +
> + for (tag = 0; tag < HSQ_NUM_SLOTS; tag++) {
> + slot = &hsq->slot[tag];
> + mrq = slot->mrq;
> + if (mrq && mrq->data &&
> + (mrq->data->blksz * mrq->data->blocks == 4096) &&
> + (mrq->data->flags & MMC_DATA_WRITE))
> + need_change++;

And following above, then we can do the below here:
mmc->hsq_depth = HSQ_PERFORMANCE_DEPTH;
break;

That should simplify and make this more efficient too, right?

> + else
> + break;
> + }
> +
> + if (need_change > 1)
> + mmc->hsq_depth = HSQ_PERFORMANCE_DEPTH;
> + else
> + mmc->hsq_depth = HSQ_NORMAL_DEPTH;
> +}
> +

[...]

Kind regards
Uffe

2023-09-15 18:00:04

by Wenchao Chen

Subject: Re: [PATCH V3 2/2] mmc: hsq: dynamic adjustment of hsq->depth

On Thu, 14 Sept 2023 at 20:57, Ulf Hansson <[email protected]> wrote:
>
> On Tue, 29 Aug 2023 at 04:05, Wenchao Chen <[email protected]> wrote:
> >
> > Increasing hsq_depth improves random write performance.
> >
> > Signed-off-by: Wenchao Chen <[email protected]>
> > ---
> > drivers/mmc/host/mmc_hsq.c | 27 +++++++++++++++++++++++++++
> > drivers/mmc/host/mmc_hsq.h | 5 +++++
> > 2 files changed, 32 insertions(+)
> >
> > diff --git a/drivers/mmc/host/mmc_hsq.c b/drivers/mmc/host/mmc_hsq.c
> > index 8556cacb21a1..0984c39108ba 100644
> > --- a/drivers/mmc/host/mmc_hsq.c
> > +++ b/drivers/mmc/host/mmc_hsq.c
> > @@ -21,6 +21,31 @@ static void mmc_hsq_retry_handler(struct work_struct *work)
> > mmc->ops->request(mmc, hsq->mrq);
> > }
> >
> > +static void mmc_hsq_modify_threshold(struct mmc_hsq *hsq)
> > +{
> > + struct mmc_host *mmc = hsq->mmc;
> > + struct mmc_request *mrq;
> > + struct hsq_slot *slot;
> > + int need_change = 0;
>
> Rather than using a variable to keep track of this, why not just do
> the below here?
>
> mmc->hsq_depth = HSQ_NORMAL_DEPTH;
>
> > + int tag;
> > +
> > + for (tag = 0; tag < HSQ_NUM_SLOTS; tag++) {
> > + slot = &hsq->slot[tag];
> > + mrq = slot->mrq;
> > + if (mrq && mrq->data &&
> > + (mrq->data->blksz * mrq->data->blocks == 4096) &&
> > + (mrq->data->flags & MMC_DATA_WRITE))
> > + need_change++;
>
> And following above, then we can do the below here:
> mmc->hsq_depth = HSQ_PERFORMANCE_DEPTH;
> break;
>
> That should simplify and make this more efficient too, right?
>

Yes, you are right. But need_change = 2, it means more reqs are allowed.
Alternatively, modify it like this:
mmc->hsq_depth = (need_change > 1) ? HSQ_PERFORMANCE_DEPTH : HSQ_NORMAL_DEPTH;

> > + else
> > + break;
> > + }
> > +
> > + if (need_change > 1)
> > + mmc->hsq_depth = HSQ_PERFORMANCE_DEPTH;
> > + else
> > + mmc->hsq_depth = HSQ_NORMAL_DEPTH;
> > +}
> > +
>
> [...]
>
> Kind regards
> Uffe