From: Gerd Hoffmann <kraxel@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>,
Sergio Lopez <slp@redhat.com>,
qemu-devel@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>,
Igor Mammedov <imammedo@redhat.com>,
Richard Henderson <rth@twiddle.net>
Subject: Re: [PATCH 00/13] microvm: add acpi support
Date: Mon, 23 Mar 2020 13:09:48 +0100 [thread overview]
Message-ID: <20200323120948.f6egd7rhfso6276p@sirius.home.kraxel.org> (raw)
In-Reply-To: <20200323065050-mutt-send-email-mst@kernel.org>
On Mon, Mar 23, 2020 at 06:51:10AM -0400, Michael S. Tsirkin wrote:
> On Thu, Mar 19, 2020 at 09:01:04AM +0100, Gerd Hoffmann wrote:
> > I know that not supporting ACPI in microvm is intentional. If you still
> > don't want ACPI this is perfectly fine, you can use the usual -no-acpi
> > switch to toggle ACPI support.
> >
> > These are the advantages you are going to loose then:
> >
> > (1) virtio-mmio device discovery without command line hacks (tweaking
> > the command line is a problem when not using direct kernel boot).
> > (2) Better IO-APIC support, we can use IRQ lines 16-23.
> > (3) ACPI power button (aka powerdown request) works.
> > (4) machine poweroff (aka S5 state) works.
>
> What is the cost though? How do boot times compare?
Well, acpi speeds up booting by one second because this delay ...
[ 0.275736] i8042: PNP: No PS/2 controller found.
[ 0.275736] i8042: Probing ports directly.
[ 1.315447] i8042: No controller found
... goes away, at least with standard distro kernels. When building
your own you can probably compile out the driver somehow, even though
something seems to select SERIO_I8042 so trying to simply flip
CONFIG_SERIO_I8042 to 'n' in .config doesn't work. And a runtime
switch seems to not be there either ...
So that ruined my plan to just time until the root filesystem is
mounted. Decided to use the "i8042: PNP: No PS/2 controller found."
line instead for a simple test (just check the kernel log timestamps,
three runs each). The ACPI initialization is already done at that
point, so it should be useful nevertheless. Here we go:
Without acpi:
0.277710
0.278852
0.279520
With acpi:
0.283917
0.284262
0.284836
So the difference is less than 0.01 seconds on my box.
cheers,
Gerd
next prev parent reply other threads:[~2020-03-23 12:10 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-19 8:01 [PATCH 00/13] microvm: add acpi support Gerd Hoffmann
2020-03-19 8:01 ` [PATCH 01/13] acpi: make build_madt() more generic Gerd Hoffmann
2020-03-19 9:34 ` Philippe Mathieu-Daudé
2020-03-19 8:01 ` [PATCH 02/13] acpi: factor out acpi_dsdt_add_fw_cfg() Gerd Hoffmann
2020-03-19 9:36 ` Philippe Mathieu-Daudé
2020-03-19 12:16 ` Igor Mammedov
2020-03-19 8:01 ` [PATCH 03/13] microvm: add isa-acpi device Gerd Hoffmann
2020-03-19 13:42 ` Igor Mammedov
2020-03-20 8:22 ` Gerd Hoffmann
2020-03-20 14:54 ` Igor Mammedov
2020-03-19 8:01 ` [PATCH 04/13] microvm: add minimal acpi support Gerd Hoffmann
2020-03-19 14:00 ` Igor Mammedov
2020-03-25 9:04 ` Gerd Hoffmann
2020-03-25 18:59 ` Igor Mammedov
2020-03-19 8:01 ` [PATCH 05/13] microvm: add acpi_dsdt_add_virtio() for x86 Gerd Hoffmann
2020-03-19 14:30 ` Igor Mammedov
2020-03-20 8:19 ` Gerd Hoffmann
2020-03-19 8:01 ` [PATCH 06/13] microvm: disable virtio-mmio cmdline hack Gerd Hoffmann
2020-03-19 8:01 ` [PATCH 07/13] [testing] seabios: update submodule to experimental microvm branch Gerd Hoffmann
2020-03-19 8:01 ` [PATCH 08/13] [testing] seabios: update config & build rules Gerd Hoffmann
2020-03-19 8:01 ` [PATCH 09/13] [testing] seabios: update binaries to experimental microvm branch Gerd Hoffmann
2020-03-19 8:01 ` [PATCH 10/13] microvm/acpi: add rtc Gerd Hoffmann
2020-03-19 8:01 ` [PATCH 11/13] microvm/acpi: add serial Gerd Hoffmann
2020-03-19 8:01 ` [PATCH 12/13] microvm: make virtio irq base runtime configurable Gerd Hoffmann
2020-03-19 8:01 ` [PATCH 13/13] microvm/acpi: use GSI 16-23 for virtio Gerd Hoffmann
2020-03-20 15:30 ` Konrad Rzeszutek Wilk
2020-03-23 10:23 ` Gerd Hoffmann
2020-03-19 8:19 ` [PATCH 00/13] microvm: add acpi support no-reply
2020-03-19 8:23 ` no-reply
2020-03-19 8:24 ` no-reply
2020-03-19 8:49 ` Paolo Bonzini
2020-03-19 9:33 ` Gerd Hoffmann
2020-03-19 9:59 ` Paolo Bonzini
2020-03-19 11:28 ` Gerd Hoffmann
2020-03-19 13:40 ` Gerd Hoffmann
2020-03-19 17:34 ` Paolo Bonzini
2020-03-20 8:32 ` Gerd Hoffmann
2020-03-20 10:41 ` Paolo Bonzini
2020-03-23 10:51 ` Michael S. Tsirkin
2020-03-23 12:09 ` Gerd Hoffmann [this message]
2020-03-23 12:16 ` Igor Mammedov
2020-03-25 9:16 ` Gerd Hoffmann
2020-03-25 9:53 ` Igor Mammedov
2020-03-25 18:56 ` Igor Mammedov
2020-03-25 12:32 ` Igor Mammedov
2020-03-25 15:03 ` Gerd Hoffmann
2020-03-25 18:44 ` Igor Mammedov
2020-03-26 7:33 ` Michael S. Tsirkin
2020-03-26 10:59 ` Igor Mammedov
2020-03-27 12:06 ` Gerd Hoffmann
2020-03-27 14:05 ` Igor Mammedov
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