Hi Geert,
Thanks for your quick reply!
On Fri, Aug 26, 2016 at 2:58 AM, Hiep Cao Minh <cm-hiep@xxxxxxxxxxx> wrote:
I'd like to ask you about R-Car Gen2 QSPI driver performance test of single,
dual and quad.
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commit 4f12b5e529e4ff274eb478ec1c2ef41358ed9577
Author: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Date: Mon Jun 2 15:38:17 2014 +0200
spi: rspi: Add DMA support for QSPI on R-Car Gen2
Enable DMA support for QSPI on R-Car Gen2, for Single, Dual, and Quad
SPI
Transfers.
Performance figures for reading from a QSPI FLASH driven at 24.375 MHz
on r8a7791/koelsch:
- Single: 1.1 Mbps PIO, 23 Mbps DMA
- Dual : 12.7 Mbps PIO, 48 Mbps DMA
- Quad : 13 Mbps PIO, 70 Mbps DMA
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Could you show me how to test these performances?
As I wanted to measure raw SPI performance, and not overhead (block
device, file system, ...) or other impact (buffer cache!), I used a patch like
the (whitespace-damaged) one at the end of this email, and:
dd if=/dev/mtd2 bs=4M count=1 of=/dev/null
Using a sufficiently large buffer size is recommended for good performance.
All of this was done in r8a7791/koelsch.
Thanks, I'll try to reproduce them as you showed me.
I have tried to reproduce them but I only got the results like this:
Enabled DMA:
Linux stable v4.7
Quad-spi： Read 3.2 MB/s Write 601 kB/s
Dual-spi： Read 3.1 MB/s Write 847 kB/s
Single-spi： Read 2.5 MB/s Write 850 kB/s
PIO:
RcarGen2_BSP linux_v3.10.101-ltsi
Quad-spi： Read 2.2 MB/s Write 1.1 MB/s
Dual-spi： Read 2.1 MB/s Write 158 kB/s
Single-spi： Read 173 kB/s Write 159 kB/s
Note that some of these are even faster than mine, probably due to
caching...
Oh!, thank you pointed it out.
And we also wonder why the reading speed in quad and dual mode are most
the same?.
(I mean they are not different very much.)
v4.7: Read 3.2 MB/s(Quad) and 3.1 MB/s(Dual),
And in your test results: 12.7 Mbps, 13 Mbps in PIO mode.
Regards,
Jinso/Hiep.
