RE: [PATCH v9 0/5] Add MMC software queue support
From: BOUGH CHEN
Date: Mon Jun 08 2020 - 02:36:09 EST
> -----Original Message-----
> From: linux-mmc-owner@xxxxxxxxxxxxxxx
> [mailto:linux-mmc-owner@xxxxxxxxxxxxxxx] On Behalf Of Baolin Wang
> Sent: 2020å2æ19æ 9:35
> To: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>; Asutosh Das
> <asutoshd@xxxxxxxxxxxxxx>; Orson Zhai <orsonzhai@xxxxxxxxx>; Chunyan
> Zhang <zhang.lyra@xxxxxxxxx>; Arnd Bergmann <arnd@xxxxxxxx>; Linus
> Walleij <linus.walleij@xxxxxxxxxx>; Baolin Wang <baolin.wang@xxxxxxxxxx>;
> linux-mmc@xxxxxxxxxxxxxxx; Linux Kernel Mailing List
> <linux-kernel@xxxxxxxxxxxxxxx>
> Subject: Re: [PATCH v9 0/5] Add MMC software queue support
>
> On Wed, Feb 19, 2020 at 7:38 AM Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> wrote:
> >
> > On Wed, 12 Feb 2020 at 05:14, Baolin Wang <baolin.wang7@xxxxxxxxx>
> wrote:
> > >
> > > Hi All,
> > >
> > > 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 set will introduce the MMC software command queue
> > > support based on command queue engine's interfaces, and set the
> > > queue depth as 64 to allow more requests can be be prepared, merged
> > > and inserted into IO scheduler, but we only allow 2 requests in
> > > flight, that is enough to let the irq handler always trigger the
> > > next request without a context switch, as well as avoiding a long latency.
> > >
> > > Moreover we can expand the MMC software queue interface to support
> > > MMC packed request or packed command instead of adding new
> > > interfaces, according to previosus discussion.
> > >
> > > Below are some comparison data with fio tool. The fio command I used
> > > is like below with changing the '--rw' parameter and enabling the
> > > direct IO flag to measure the actual hardware transfer speed in 4K block
> size.
> > >
> > > ./fio --filename=/dev/mmcblk0p30 --direct=1 --iodepth=20 --rw=read
> > > --bs=4K --size=1G --group_reporting --numjobs=20 --name=test_read
> > >
> > > My eMMC card working at HS400 Enhanced strobe mode:
> > > [ 2.229856] mmc0: new HS400 Enhanced strobe MMC card at address
> 0001
> > > [ 2.237566] mmcblk0: mmc0:0001 HBG4a2 29.1 GiB
> > > [ 2.242621] mmcblk0boot0: mmc0:0001 HBG4a2 partition 1 4.00 MiB
> > > [ 2.249110] mmcblk0boot1: mmc0:0001 HBG4a2 partition 2 4.00 MiB
> > > [ 2.255307] mmcblk0rpmb: mmc0:0001 HBG4a2 partition 3 4.00 MiB,
> chardev (248:0)
> > >
> > > 1. Without MMC software queue
> > > I tested 5 times for each case and output a average speed.
> > >
> > > 1) Sequential read:
> > > Speed: 59.4MiB/s, 63.4MiB/s, 57.5MiB/s, 57.2MiB/s, 60.8MiB/s Average
> > > speed: 59.66MiB/s
> > >
> > > 2) Random read:
> > > Speed: 26.9MiB/s, 26.9MiB/s, 27.1MiB/s, 27.1MiB/s, 27.2MiB/s Average
> > > speed: 27.04MiB/s
> > >
> > > 3) Sequential write:
> > > Speed: 71.6MiB/s, 72.5MiB/s, 72.2MiB/s, 64.6MiB/s, 67.5MiB/s Average
> > > speed: 69.68MiB/s
> > >
> > > 4) Random write:
> > > Speed: 36.3MiB/s, 35.4MiB/s, 38.6MiB/s, 34MiB/s, 35.5MiB/s Average
> > > speed: 35.96MiB/s
> > >
> > > 2. With MMC software queue
> > > I tested 5 times for each case and output a average speed.
> > >
> > > 1) Sequential read:
> > > Speed: 59.2MiB/s, 60.4MiB/s, 63.6MiB/s, 60.3MiB/s, 59.9MiB/s Average
> > > speed: 60.68MiB/s
> > >
> > > 2) Random read:
> > > Speed: 31.3MiB/s, 31.4MiB/s, 31.5MiB/s, 31.3MiB/s, 31.3MiB/s Average
> > > speed: 31.36MiB/s
> > >
> > > 3) Sequential write:
> > > Speed: 71MiB/s, 71.8MiB/s, 72.3MiB/s, 72.2MiB/s, 71MiB/s Average
> > > speed: 71.66MiB/s
> > >
> > > 4) Random write:
> > > Speed: 68.9MiB/s, 68.7MiB/s, 68.8MiB/s, 68.6MiB/s, 68.8MiB/s Average
> > > speed: 68.76MiB/s
> > >
> > > Form above data, we can see the MMC software queue can help to
> > > improve some performance obviously for random read and write, though
> > > no obvious improvement for sequential read and write.
> > >
> > > Any comments are welcome. Thanks a lot.
> > >
Hi Baolin,
I refer to your code, and add the software queue support on i.MX based on the Linux next-20200602, but unfortunately, I see an obvious performance drop when change to use software queue.
I test on our imx850-evk board, with eMMC soldered.
From the result listing below, only random write has a little performance improve, for others, seems performance drop a lot.
I noticed that, this software queue need no-removable card, any other limitation? For host?
From the code logic, software queue complete the request in irq handler, seems no other change, I do not figure out why this will trigger a performance drop on my platform. Any comment would be appreciate!
Without software queue, normal read/write method:
Sequential read: 56MB/s
Random read: 23.5MB/s
Sequential write: 43.7MB/s
Random write: 19MB/s
With mmc software queue:
Sequential read: 33.5MB/s
Random read: 18.7 MB/s
Sequential write: 37.7MB/s
Random write: 19.8MB/s
Here, I also list my change code to support software queue
diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index eb85237bf2d6..996b8cc5c381 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -254,6 +254,7 @@ config MMC_SDHCI_ESDHC_IMX
depends on MMC_SDHCI_PLTFM
select MMC_SDHCI_IO_ACCESSORS
select MMC_CQHCI
+ select MMC_HSQ
help
This selects the Freescale eSDHC/uSDHC controller support
found on i.MX25, i.MX35 i.MX5x and i.MX6x.
diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index 1d7f84b23a22..6f163695b08d 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -29,6 +29,7 @@
#include "sdhci-pltfm.h"
#include "sdhci-esdhc.h"
#include "cqhci.h"
+#include "mmc_hsq.h"
#define ESDHC_SYS_CTRL_DTOCV_MASK 0x0f
#define ESDHC_CTRL_D3CD 0x08
@@ -1220,6 +1221,15 @@ static u32 esdhc_cqhci_irq(struct sdhci_host *host, u32 intmask)
return 0;
}
+static void esdhc_request_done(struct sdhci_host *host, struct mmc_request *mrq)
+{
+ /* Validate if the request was from software queue firstly. */
+ if (mmc_hsq_finalize_request(host->mmc, mrq))
+ return;
+
+ mmc_request_done(host->mmc, mrq);
+}
+
static struct sdhci_ops sdhci_esdhc_ops = {
.read_l = esdhc_readl_le,
.read_w = esdhc_readw_le,
@@ -1237,6 +1247,7 @@ static struct sdhci_ops sdhci_esdhc_ops = {
.set_uhs_signaling = esdhc_set_uhs_signaling,
.reset = esdhc_reset,
.irq = esdhc_cqhci_irq,
+ .request_done = esdhc_request_done,
};
static const struct sdhci_pltfm_data sdhci_esdhc_imx_pdata = {
@@ -1301,6 +1312,19 @@ static void sdhci_esdhc_imx_hwinit(struct sdhci_host *host)
writel(tmp, host->ioaddr + ESDHC_VEND_SPEC2);
host->quirks &= ~SDHCI_QUIRK_NO_BUSY_IRQ;
+
+ /*
+ * On i.MX8MM, we are running Dual Linux OS, with 1st Linux using SD Card
+ * as rootfs storage, 2nd Linux using eMMC as rootfs storage. We let the
+ * the 1st linux configure power/clock for the 2nd Linux.
+ *
+ * When the 2nd Linux is booting into rootfs stage, we let the 1st Linux
+ * to destroy the 2nd linux, then restart the 2nd linux, we met SDHCI dump.
+ * After we clear the pending interrupt and halt CQCTL, issue gone.
+ */
+ tmp = cqhci_readl(cq_host, CQHCI_IS);
+ cqhci_writel(cq_host, tmp, CQHCI_IS);
+ cqhci_writel(cq_host, CQHCI_HALT, CQHCI_CTL);
}
if (imx_data->socdata->flags & ESDHC_FLAG_STD_TUNING) {
@@ -1351,9 +1375,6 @@ static void sdhci_esdhc_imx_hwinit(struct sdhci_host *host)
* After we clear the pending interrupt and halt CQCTL, issue gone.
*/
if (cq_host) {
- tmp = cqhci_readl(cq_host, CQHCI_IS);
- cqhci_writel(cq_host, tmp, CQHCI_IS);
- cqhci_writel(cq_host, CQHCI_HALT, CQHCI_CTL);
}
}
}
@@ -1555,6 +1576,7 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev)
struct sdhci_pltfm_host *pltfm_host;
struct sdhci_host *host;
struct cqhci_host *cq_host;
+ struct mmc_hsq *hsq;
int err;
struct pltfm_imx_data *imx_data;
@@ -1664,6 +1686,16 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev)
err = cqhci_init(cq_host, host->mmc, false);
if (err)
goto disable_ahb_clk;
+ } else if (esdhc_is_usdhc(imx_data)) {
+ hsq = devm_kzalloc(&pdev->dev, sizeof(*hsq), GFP_KERNEL);
+ if (!hsq) {
+ err = -ENOMEM;
+ goto disable_ahb_clk;
+ }
+
+ err = mmc_hsq_init(hsq, host->mmc);
+ if (err)
+ goto disable_ahb_clk;
}
if (of_id)
@@ -1673,6 +1705,11 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev)
if (err)
goto disable_ahb_clk;
+ if (!mmc_card_is_removable(host->mmc))
+ host->mmc_host_ops.request_atomic = sdhci_request_atomic;
+ else
+ host->always_defer_done = true;
+
sdhci_esdhc_imx_hwinit(host);
err = sdhci_add_host(host);
@@ -1737,6 +1774,8 @@ static int sdhci_esdhc_suspend(struct device *dev)
ret = cqhci_suspend(host->mmc);
if (ret)
return ret;
+ } else if (esdhc_is_usdhc(imx_data)) {
+ mmc_hsq_suspend(host->mmc);
}
if ((imx_data->socdata->flags & ESDHC_FLAG_STATE_LOST_IN_LPMODE) &&
@@ -1764,6 +1803,8 @@ static int sdhci_esdhc_suspend(struct device *dev)
static int sdhci_esdhc_resume(struct device *dev)
{
struct sdhci_host *host = dev_get_drvdata(dev);
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host);
int ret;
ret = pinctrl_pm_select_default_state(dev);
@@ -1777,8 +1818,11 @@ static int sdhci_esdhc_resume(struct device *dev)
if (ret)
return ret;
- if (host->mmc->caps2 & MMC_CAP2_CQE)
+ if (host->mmc->caps2 & MMC_CAP2_CQE) {
ret = cqhci_resume(host->mmc);
+ } else if (esdhc_is_usdhc(imx_data)) {
+ mmc_hsq_resume(host->mmc);
+ }
if (!ret)
ret = mmc_gpio_set_cd_wake(host->mmc, false);
@@ -1799,6 +1843,8 @@ static int sdhci_esdhc_runtime_suspend(struct device *dev)
ret = cqhci_suspend(host->mmc);
if (ret)
return ret;
+ } else if (esdhc_is_usdhc(imx_data)) {
+ mmc_hsq_suspend(host->mmc);
}
ret = sdhci_runtime_suspend_host(host);
@@ -1851,8 +1897,11 @@ static int sdhci_esdhc_runtime_resume(struct device *dev)
if (err)
goto disable_ipg_clk;
- if (host->mmc->caps2 & MMC_CAP2_CQE)
+ if (host->mmc->caps2 & MMC_CAP2_CQE) {
err = cqhci_resume(host->mmc);
+ } else if (esdhc_is_usdhc(imx_data)) {
+ mmc_hsq_resume(host->mmc);
+ }
return err;
> > > Changes from v8:
> > > - Add more description in the commit message.
> > > - Optimize the failure log when calling cqe_enable().
> > >
> > > Changes from v7:
> > > - Add reviewed tag from Arnd.
> > > - Use the 'hsq' acronym for varibles and functions in the core layer.
> > > - Check the 'card->ext_csd.cmdq_en' in cqhci.c to make sure the CQE
> > > can work normally.
> > > - Add a new patch to enable the host software queue for the SD card.
> > > - Use the default MMC queue depth for host software queue.
> > >
> > > Changes from v6:
> > > - Change the patch order and set host->always_defer_done = true for
> > > the Spreadtrum host driver.
> > >
> > > Changes from v5:
> > > - Modify the condition of defering to complete request suggested by
> Adrian.
> > >
> > > Changes from v4:
> > > - Add a seperate patch to introduce a variable to defer to complete
> > > data requests for some host drivers, when using host software queue.
> > >
> > > Changes from v3:
> > > - Use host software queue instead of sqhci.
> > > - Fix random config building issue.
> > > - Change queue depth to 32, but still only allow 2 requests in flight.
> > > - Update the testing data.
> > >
> > > Changes from v2:
> > > - Remove reference to 'struct cqhci_host' and 'struct cqhci_slot',
> > > instead adding 'struct sqhci_host', which is only used by software queue.
> > >
> > > Changes from v1:
> > > - Add request_done ops for sdhci_ops.
> > > - Replace virtual command queue with software queue for functions
> > > and variables.
> > > - Rename the software queue file and add sqhci.h header file.
> > >
> > > Baolin Wang (5):
> > > mmc: Add MMC host software queue support
> > > mmc: core: Enable the MMC host software queue for the SD card
> > > mmc: host: sdhci: Add request_done ops for struct sdhci_ops
> > > mmc: host: sdhci: Add a variable to defer to complete requests if
> > > needed
> > > mmc: host: sdhci-sprd: Add software queue support
> > >
> > > drivers/mmc/core/block.c | 61 ++++++++
> > > drivers/mmc/core/mmc.c | 18 ++-
> > > drivers/mmc/core/queue.c | 22 ++-
> > > drivers/mmc/core/sd.c | 10 ++
> > > drivers/mmc/host/Kconfig | 8 +
> > > drivers/mmc/host/Makefile | 1 +
> > > drivers/mmc/host/cqhci.c | 8 +-
> > > drivers/mmc/host/mmc_hsq.c | 343
> +++++++++++++++++++++++++++++++++++++++++
> > > drivers/mmc/host/mmc_hsq.h | 30 ++++
> > > drivers/mmc/host/sdhci-sprd.c | 28 ++++
> > > drivers/mmc/host/sdhci.c | 14 +-
> > > drivers/mmc/host/sdhci.h | 3 +
> > > include/linux/mmc/host.h | 3 +
> > > 13 files changed, 534 insertions(+), 15 deletions(-) create mode
> > > 100644 drivers/mmc/host/mmc_hsq.c create mode 100644
> > > drivers/mmc/host/mmc_hsq.h
> > >
> > > --
> > > 1.7.9.5
> > >
> >
> > Applied for next, thanks! Also, thanks for your patience while moving
> > forward during the reviews!
>
> I am very appreciated for you and Arnd's good sugestion when introducing the
> hsq.
>
> >
> > Note, I did some amending of patch1 to resolve some checkpatch
> > warnings. SPDX licence and Kconfig help texts, please have a look and
> > tell if there are something that doesn't look good.
>
> Thanks for your help and looks good to me.