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Subject: Re: [PATCH v2] of: use hash based search in of_find_node_by_phandle
To:     Frank Rowand <frowand.list@gmail.com>, robh+dt@kernel.org,
        devicetree@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org
References: <1516955496-17236-1-git-send-email-cpandya@codeaurora.org>
 <2d877704-47c5-c1fc-1b89-976cd9b1ccaa@gmail.com>
From:   Chintan Pandya <cpandya@codeaurora.org>
Message-ID: <7ebd275d-07ba-1972-011a-d05e53233a01@codeaurora.org>
Date:   Tue, 30 Jan 2018 13:34:40 +0530
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> (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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