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* Re: Subject: [PATCH] arm/kernel/head.S: optimize __create_page_tables function
       [not found] <CAKy1Xqcnkfm7Dn9UvJ7Ufio-szQ75kbGS+GurBjuUFBydi21GA@mail.gmail.com>
@ 2020-02-24 11:05 ` Russell King - ARM Linux admin
       [not found]   ` <CAKy1XqdBt=LNpk-7Rt2LXU3tky=fS9jHxD0DV5CKh4wYWxFVRQ@mail.gmail.com>
  0 siblings, 1 reply; 2+ messages in thread
From: Russell King - ARM Linux admin @ 2020-02-24 11:05 UTC (permalink / raw)
  To: yifeng wu; +Cc: linux-arm-kernel, linux-kernel

On Mon, Feb 24, 2020 at 06:38:22PM +0800, yifeng wu wrote:
> I'm sorry that my computer can't configure git send-email, so I'll send you
> the patch as an attachment, and I'll show my changes in the email text,
> expecting a reply -------an engineer who submitted the patch for the first
> time。

Please explain why you wish to optimise this, and how much effect it
has.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: Subject: [PATCH] arm/kernel/head.S: optimize __create_page_tables function
       [not found]   ` <CAKy1XqdBt=LNpk-7Rt2LXU3tky=fS9jHxD0DV5CKh4wYWxFVRQ@mail.gmail.com>
@ 2020-02-24 12:03     ` Russell King - ARM Linux admin
  0 siblings, 0 replies; 2+ messages in thread
From: Russell King - ARM Linux admin @ 2020-02-24 12:03 UTC (permalink / raw)
  To: yifeng wu; +Cc: linux-arm-kernel, linux-kernel

Hi,

On Mon, Feb 24, 2020 at 07:54:07PM +0800, yifeng wu wrote:
> Thank you very much for your reply.
> I have tested on my machine. It takes about 0.5 seconds to copy the memory
> (16M size) with "str" instruction, and only 0.1 seconds with "stmia"

ITYM 16k.  You say "copy" but we're setting memory to zero.  I'm quite
surprised by that difference, which CPU was this measured on?

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2020-02-24 11:05 ` Subject: [PATCH] arm/kernel/head.S: optimize __create_page_tables function Russell King - ARM Linux admin
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2020-02-24 12:03     ` Russell King - ARM Linux admin

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