qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
From: "Philippe Mathieu-Daudé" <philmd@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>,
	Niek Linnenbank <nieklinnenbank@gmail.com>
Cc: Igor Mammedov <imammedo@redhat.com>,
	qemu-arm <qemu-arm@nongnu.org>,
	Richard Henderson <richard.henderson@linaro.org>,
	QEMU Developers <qemu-devel@nongnu.org>,
	Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: Sudden slowdown of ARM emulation in master
Date: Wed, 26 Feb 2020 09:44:19 +0100	[thread overview]
Message-ID: <ffa87cab-e85c-c381-289a-fdf1ef07b45a@redhat.com> (raw)
In-Reply-To: <CAFEAcA_azGqyzbxegpK8ch_bums6Wtd=U7cNxvM=bAJ-Ld2DDA@mail.gmail.com>

On 2/26/20 9:41 AM, Peter Maydell wrote:
> On Tue, 25 Feb 2020 at 23:08, Niek Linnenbank <nieklinnenbank@gmail.com> wrote:
> 
>> Just now I was working on some small fixes for the cubieboard machine and rebasing my Allwinner H3 branches.
>> While doing some testing, I noticed that suddenly the machines were much slower than before.
>> I only see this happening when I rebase to this commit:
>>     ca6155c0f2bd39b4b4162533be401c98bd960820 ("Merge tag 'patchew/20200219160953.13771-1-imammedo@redhat.com' of https://github.com/patchew-project/qemu into HEAD")
> 
> Yeah, I noticed a slowdown yesterday as well, but haven't tracked it down
> as yet. The first thing would be to do a git bisect to try to narrow
> down what commit caused it.

My guess: biggest chunk of memory is the DRAM, registered as "fast RAM" 
by QEMU, but the SoCs provide SRAM which is supposed to be faster. Not 
anymore with QEMU. And Linux try to use the SRAM when possible.



  reply	other threads:[~2020-02-26  8:45 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-25 23:07 Sudden slowdown of ARM emulation in master Niek Linnenbank
2020-02-26  8:41 ` Peter Maydell
2020-02-26  8:44   ` Philippe Mathieu-Daudé [this message]
2020-02-26  8:48     ` Peter Maydell
2020-02-26  8:51       ` Philippe Mathieu-Daudé
2020-02-26  8:45   ` Howard Spoelstra
2020-02-26  9:11     ` Igor Mammedov
2020-02-26  9:19 ` Igor Mammedov
2020-02-26  9:32   ` Howard Spoelstra
2020-02-26 10:14     ` Igor Mammedov
2020-02-26 10:03   ` Peter Maydell
2020-02-26 10:36     ` Mark Cave-Ayland
2020-02-26 14:13     ` Alex Bennée
2020-02-26 14:45       ` Igor Mammedov
2020-02-26 15:29         ` Alex Bennée

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=ffa87cab-e85c-c381-289a-fdf1ef07b45a@redhat.com \
    --to=philmd@redhat.com \
    --cc=imammedo@redhat.com \
    --cc=nieklinnenbank@gmail.com \
    --cc=pbonzini@redhat.com \
    --cc=peter.maydell@linaro.org \
    --cc=qemu-arm@nongnu.org \
    --cc=qemu-devel@nongnu.org \
    --cc=richard.henderson@linaro.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).