From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: "ulf.hansson@linaro.org" <ulf.hansson@linaro.org>,
"wsa+renesas@sang-engineering.com"
<wsa+renesas@sang-engineering.com>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
"linux-renesas-soc@vger.kernel.org"
<linux-renesas-soc@vger.kernel.org>
Subject: RE: [PATCH 0/3] mmc: renesas_sdhi_internal_dmac: improve performance by using IOMMU
Date: Tue, 7 May 2019 08:58:43 +0000 [thread overview]
Message-ID: <OSBPR01MB3174BFC6487E29AF4EA5E150D8310@OSBPR01MB3174.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <20190426094611.GD1031@kunai>
Hi Wolfram-san,
> From: Wolfram Sang, Sent: Friday, April 26, 2019 6:46 PM
>
> Hi Shimoda-san,
>
> thanks for working on this!
>
> > Please refer to the end of this email about the performance.
>
> Yes, nice improvements, great!
Thanks!
> > (I beleive if the performance is improved, the CPU load is also increased.)
>
> I do wonder about this a bit, though. IPMMU and DMA shouldn't be that
> much expensive for the CPU, or? Am I overlooking something?
I'm guessing that a user land app (in this case bonnie++) consumes CPU load for some reason.
I'll experiment whether my guess is correct or not by using usb 3.0 host like below tomorrow:
- case 1: usb 3.0 host + usb SSD as SuperSpeed (IOMMU is disabled).
- case 2: usb 3.0 host + usb SSD via a usb2.0 hub as high-speed (IOMMU is disabled).
Best regards,
Yoshihiro Shimoda
> Kind regards,
>
> Wolfram
next prev parent reply other threads:[~2019-05-07 8:58 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-26 5:18 [PATCH 0/3] mmc: renesas_sdhi_internal_dmac: improve performance by using IOMMU Yoshihiro Shimoda
2019-04-26 5:18 ` [PATCH 1/3] mmc: tmio: add init_card ops Yoshihiro Shimoda
2019-04-26 9:15 ` Wolfram Sang
2019-04-26 9:45 ` Simon Horman
2019-04-26 9:56 ` Wolfram Sang
2019-04-26 10:17 ` Simon Horman
2019-04-26 5:18 ` [PATCH 2/3] mmc: tmio: No memory size limitation if runs on IOMMU Yoshihiro Shimoda
2019-04-26 8:09 ` Sergei Shtylyov
2019-04-26 9:17 ` Wolfram Sang
2019-05-07 7:13 ` Yoshihiro Shimoda
2019-04-26 9:45 ` Simon Horman
2019-04-26 5:18 ` [PATCH 3/3] mmc: renesas_sdhi_internal_dmac: use multiple segments if possible Yoshihiro Shimoda
2019-04-26 9:37 ` Wolfram Sang
2019-05-07 7:27 ` Yoshihiro Shimoda
2019-04-26 9:45 ` Simon Horman
2019-04-26 9:46 ` [PATCH 0/3] mmc: renesas_sdhi_internal_dmac: improve performance by using IOMMU Wolfram Sang
2019-05-07 8:58 ` Yoshihiro Shimoda [this message]
2019-05-08 4:28 ` Yoshihiro Shimoda
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