From: Christian Loehle <christian.loehle@arm.com>
To: Lucas Stach <l.stach@pengutronix.de>,
ziniu.wang_1@nxp.com, adrian.hunter@intel.com,
ulf.hansson@linaro.org
Cc: imx@lists.linux.dev, s32@nxp.com, shawnguo@kernel.org,
s.hauer@pengutronix.de, linux-mmc@vger.kernel.org,
linux-kernel@vger.kernel.org, haibo.chen@nxp.com,
kernel@pengutronix.de, festevam@gmail.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] mmc: sdhci-esdhc-imx: improve imx8mq emmc/sd read performance
Date: Mon, 17 Feb 2025 12:02:04 +0000 [thread overview]
Message-ID: <3e79d92a-6ec9-4c7a-a836-1306678c2bef@arm.com> (raw)
In-Reply-To: <ab721b4a96495516f5149e91f3e4764014e39ba6.camel@pengutronix.de>
On 2/17/25 11:58, Lucas Stach wrote:
> Hi Luke,
>
> Am Montag, dem 17.02.2025 um 19:06 +0800 schrieb ziniu.wang_1@nxp.com:
>> From: Luke Wang <ziniu.wang_1@nxp.com>
>>
>> Compared with kernel 6.1, imx8mq eMMC/SD read performance drops by about
>> 30% with kernel 6.6.
>>
>> The eMMC/SD read thread will be put to sleep until the hardware completes
>> data transfer. Normally, the read thread will be woken up immediately
>> when the data transfer is completed. However, due to a known ic bug, if
>> imx8mq is in cpuidle, it will take a long time (about 500us) to exit
>> cpuidle. As a result, the read thread cannot immediately read the next
>> data block, affecting the read performance.
>>
> Is this really a problem with the upstream kernel? i.MX8MQ upstream
> does not use the deeper PSCI idle states, but only uses WFI, so I doubt
> that upstream is affected by this issue.
>
> Regards,
> Lucas
Furthermore if that were to be the case the correct solution would probably
to have that reflected in the dts, too?
next prev parent reply other threads:[~2025-02-17 12:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-17 11:06 [PATCH] mmc: sdhci-esdhc-imx: improve imx8mq emmc/sd read performance ziniu.wang_1
2025-02-17 11:52 ` Bough Chen
2025-02-17 11:56 ` Fabio Estevam
2025-02-17 11:58 ` Lucas Stach
2025-02-17 12:02 ` Christian Loehle [this message]
2025-02-18 3:09 ` [EXT] " Luke Wang
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