Re: [PATCH v2] of: use hash based search in of_find_node_by_phandle

From: Chintan Pandya
Date: Tue Jan 30 2018 - 03:04:51 EST


(1)

Can you point me to the driver code that is invoking
the search?
There are many locations. Few of them being,
https://source.codeaurora.org/quic/la/kernel/msm-4.9/tree/drivers/of/irq.c?h=msm-4.9#n214
https://source.codeaurora.org/quic/la/kernel/msm-4.9/tree/drivers/irqchip/irq-gic-v3.c?h=msm-4.9#n1107
https://source.codeaurora.org/quic/la/kernel/msm-4.9/tree/drivers/clk/msm/msm-clock-controller.c?h=msm-4.9#n492

(2)

And also the .dts devicetree source file that you are seeing
large overhead with.
SDM670 DTS tree starts here.
https://source.codeaurora.org/quic/la/kernel/msm-4.9/tree/arch/arm64/boot/dts/qcom/sdm670.dtsi?h=msm-4.9


(3) -- this one is less important, but if the info is easily
available to you

Sorry about dribbling out questions instead of all at once....

What is the hardware you are testing this on?
SDM670
Processor?
Kryo-300 Silver
Cache size?
From DT,
L1 32KB (per CPU)
L2 128KB (per CPU)
L3 1MB (total)
Memory size?
6GB
Processor frequency?
Max 1.7GHz for core 0. Not sure about boot time frequency.
Any other attribute of the system that will help me understand
the boot performance you are seeing?
I'm not able to profile of_find_node_by_phandle specifically as timers are
not up by then. So, just observing overall boot time for comparison.

My recent results were taken on debug_defconfig which has many performance
slowing code. So, gap between base-build and w/ the test patches would be
more than the actual production build.

Thanks,
Chintan

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