Commit 68df98c4 authored by Wenchao Chen's avatar Wenchao Chen Committed by Ulf Hansson
Browse files

mmc: hsq: Improve random I/O write performance for 4k buffers 



By dynamically adjusting the host->hsq_depth, based upon the buffer size
being 4k and that we get at least two I/O write requests in flight, we can
improve the throughput a bit. This is typical for a random I/O write
pattern.

More precisely, by dynamically changing the number of requests in flight
from 2 to 5, we can on some platforms observe ~4-5% increase in throughput.

Signed-off-by: default avatarWenchao Chen <wenchao.chen@unisoc.com>
Link: https://lore.kernel.org/r/20230919074707.25517-3-wenchao.chen@unisoc.com


[Ulf: Re-wrote the commitmsg, minor adjustment to the code - all to clarify.]
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 2e2b5479

drivers/mmc/host/mmc_hsq.c

+21 −0
Original line number Diff line number Diff line
@@ -21,6 +21,25 @@ 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;

	unsigned int tag, need_change = 0;



	mmc->hsq_depth = HSQ_NORMAL_DEPTH;

	for (tag = 0; tag < HSQ_NUM_SLOTS; tag++) {

		mrq = hsq->slot[tag].mrq;

		if (mrq && mrq->data &&

		   (mrq->data->blksz * mrq->data->blocks == 4096) &&

		   (mrq->data->flags & MMC_DATA_WRITE) &&

		   (++need_change == 2)) {

			mmc->hsq_depth = HSQ_PERFORMANCE_DEPTH;

			break;

		}

	}

}



static void mmc_hsq_pump_requests(struct mmc_hsq *hsq)

{

	struct mmc_host *mmc = hsq->mmc;
@@ -42,6 +61,8 @@ static void mmc_hsq_pump_requests(struct mmc_hsq *hsq) 
		return;

	}



	mmc_hsq_modify_threshold(hsq);



	slot = &hsq->slot[hsq->next_tag];

	hsq->mrq = slot->mrq;

	hsq->qcnt--;

drivers/mmc/host/mmc_hsq.h

+5 −0
Original line number Diff line number Diff line
@@ -10,6 +10,11 @@ 
 * flight to avoid a long latency.

 */

#define HSQ_NORMAL_DEPTH	2

/*

 * For 4k random writes, we allow hsq_depth to increase to 5

 * for better performance.

 */

#define HSQ_PERFORMANCE_DEPTH	5



struct hsq_slot {

	struct mmc_request *mrq;