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4d586b5724
The DFI is a unit which is suitable for measuring DDR utilization, but
so far it could only be used as an event driver for the DDR frequency
scaling driver. This adds perf support to the DFI driver.
Usage with the 'perf' tool can look like:
perf stat -a -e rockchip_ddr/cycles/,\
rockchip_ddr/read-bytes/,\
rockchip_ddr/write-bytes/,\
rockchip_ddr/bytes/ sleep 1
Performance counter stats for 'system wide':
1582524826 rockchip_ddr/cycles/
1802.25 MB rockchip_ddr/read-bytes/
1793.72 MB rockchip_ddr/write-bytes/
3595.90 MB rockchip_ddr/bytes/
1.014369709 seconds time elapsed
perf support has been tested on a RK3568 and a RK3399, the latter with
dual channel DDR.
Link: https://lore.kernel.org/all/20231019064819.3496740-1-s.hauer@pengutronix.de/
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
[cw00.choi: Fix typo from 'write_acccess' to 'write_access']
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.