All of lore.kernel.org
 help / color / mirror / Atom feed
From: Vijay Balakrishna <vijayb@linux.microsoft.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Linux kernel mailing list <linux-kernel@vger.kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	Nicolas Saenz Julienne <nsaenz@kernel.org>
Subject: Re: [arm64] kernel boot slowdown in v5.10.19 -> v5.10.42 update
Date: Fri, 28 Jan 2022 10:03:09 -0800	[thread overview]
Message-ID: <7e43a7e9-f299-1d6d-8b61-425793abcc3e@linux.microsoft.com> (raw)
In-Reply-To: <YfPcNy3JcnwuJNMx@arm.com>



On 1/28/2022 4:06 AM, Catalin Marinas wrote:
> On Mon, Jan 24, 2022 at 03:03:48PM -0800, Vijay Balakrishna wrote:
>> We noticed 150ms kernel boot slowdown back in June, 2021, when moving from
>> v5.10.19 to v5.10.42.  This on a 8GB SoC.  Only recently we investigated
>> this issue and found the regression is introduced by a change in map_mem()
>> (paging_init() -> map_mem() -> __map_memblock(), in particular "map all the
>> memory banks" for loop) by patch
>>
>> 2687275a5843d1089687f08fc64eb3f3b026a169
>> arm64: Force NO_BLOCK_MAPPINGS if crashkernel reservation is required
>>
>> above is a follow up to
>>
>> 0a30c53573b07d5561457e41fb0ab046cd857da5
>> arm64: mm: Move reserve_crashkernel() into mem_init())
>>
>> which deferred crashkernel reservation into mem_init().
>>
>> The ~150ms slowdown disappears on booting without "crashkernel=.." on kernel
>> command-line.
> 
> Is CONFIG_RODATA_FULL_DEFAULT_ENABLED set in your config file? It may
> cause the same slowdown. I suspect it's because we end up mapping the
> RAM at the page granularity so more loops and slightly higher TLB
> pressure. Not sure we can do much about >

Catalin,

Thanks for your reply.

CONFIG_RODATA_FULL_DEFAULT_ENABLED is not set in our config for boot 
time performance reasons.

WARNING: multiple messages have this Message-ID (diff)
From: Vijay Balakrishna <vijayb@linux.microsoft.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Linux kernel mailing list <linux-kernel@vger.kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	Nicolas Saenz Julienne <nsaenz@kernel.org>
Subject: Re: [arm64] kernel boot slowdown in v5.10.19 -> v5.10.42 update
Date: Fri, 28 Jan 2022 10:03:09 -0800	[thread overview]
Message-ID: <7e43a7e9-f299-1d6d-8b61-425793abcc3e@linux.microsoft.com> (raw)
In-Reply-To: <YfPcNy3JcnwuJNMx@arm.com>



On 1/28/2022 4:06 AM, Catalin Marinas wrote:
> On Mon, Jan 24, 2022 at 03:03:48PM -0800, Vijay Balakrishna wrote:
>> We noticed 150ms kernel boot slowdown back in June, 2021, when moving from
>> v5.10.19 to v5.10.42.  This on a 8GB SoC.  Only recently we investigated
>> this issue and found the regression is introduced by a change in map_mem()
>> (paging_init() -> map_mem() -> __map_memblock(), in particular "map all the
>> memory banks" for loop) by patch
>>
>> 2687275a5843d1089687f08fc64eb3f3b026a169
>> arm64: Force NO_BLOCK_MAPPINGS if crashkernel reservation is required
>>
>> above is a follow up to
>>
>> 0a30c53573b07d5561457e41fb0ab046cd857da5
>> arm64: mm: Move reserve_crashkernel() into mem_init())
>>
>> which deferred crashkernel reservation into mem_init().
>>
>> The ~150ms slowdown disappears on booting without "crashkernel=.." on kernel
>> command-line.
> 
> Is CONFIG_RODATA_FULL_DEFAULT_ENABLED set in your config file? It may
> cause the same slowdown. I suspect it's because we end up mapping the
> RAM at the page granularity so more loops and slightly higher TLB
> pressure. Not sure we can do much about >

Catalin,

Thanks for your reply.

CONFIG_RODATA_FULL_DEFAULT_ENABLED is not set in our config for boot 
time performance reasons.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2022-01-28 18:03 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-24 23:03 [arm64] kernel boot slowdown in v5.10.19 -> v5.10.42 update Vijay Balakrishna
2022-01-24 23:03 ` Vijay Balakrishna
2022-01-28 12:06 ` Catalin Marinas
2022-01-28 12:06   ` Catalin Marinas
2022-01-28 18:03   ` Vijay Balakrishna [this message]
2022-01-28 18:03     ` Vijay Balakrishna
2022-02-09 21:47     ` Vijay Balakrishna
2022-02-09 21:47       ` Vijay Balakrishna

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=7e43a7e9-f299-1d6d-8b61-425793abcc3e@linux.microsoft.com \
    --to=vijayb@linux.microsoft.com \
    --cc=catalin.marinas@arm.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=nsaenz@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.