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* Re: [PATCH] mmc: core: Add packed command for eMMC4.5 device
@ 2011-11-16 11:51 merez
  2011-11-17  2:23 ` Seungwon Jeon
  0 siblings, 1 reply; 4+ messages in thread
From: merez @ 2011-11-16 11:51 UTC (permalink / raw)
  To: Seungwon Jeon
  Cc: svenkatr, linux-mmc, 'Chris Ball',
	linux-kernel, linux-samsung-soc, kgene.kim, dh.han

> +			if (reqs >= 2) {
> +				mmc_blk_packed_hdr_wrq_prep(mq->mqrq_cur, card, mq, reqs);
> +				if (rq_data_dir(rqc) == READ) {
> +					areq = &mq->mqrq_cur->mmc_active;
> +					mmc_wait_for_req(card->host, areq->mrq);
Packing read requests requires preparation of two requests. After sending
the header we wait for its completion before sending the next request
(mmc_wait_for_req is used). Therefore, if we try to pack 2 read requests
we might end up with worse performance in comparison to sending each
request by itself (which allows the preparation of one request while the
other is sent).
I suggest to check the size of the packed commands list and in case it is
less than 3 send the requests one by one. If you move mmc_blk_chk_packable
to queue.c after the first fetch this change should be very easy and can
be done by removing the requests from the packed_list and calling issue_fn
for each one of them.

Thanks,
Maya Erez
Consultant for Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum







^ permalink raw reply	[flat|nested] 4+ messages in thread
[parent not found: <1319712841-28579-1-git-send-email-tgih.jun@samsung.com>]

end of thread, other threads:[~2011-11-20 19:41 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-11-16 11:51 [PATCH] mmc: core: Add packed command for eMMC4.5 device merez
2011-11-17  2:23 ` Seungwon Jeon
2011-11-20 19:41   ` merez
     [not found] <1319712841-28579-1-git-send-email-tgih.jun@samsung.com>
     [not found] ` <CANfBPZ_i3wcPkBnv-wOYbSUib=0k9bpem3ZGWg4TcjNE9NZywg@mail.gmail.com>
2011-10-28  5:44   ` Seungwon Jeon

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