From: "Richard W.M. Jones" <rjones@redhat.com>
To: Kevin O'Connor <kevin@koconnor.net>
Cc: marc.mari.barcelo@gmail.com, Paolo Bonzini <pbonzini@redhat.com>,
qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@gmail.com>
Subject: Re: [Qemu-devel] Why is SeaBIOS used with -kernel?
Date: Fri, 1 Apr 2016 16:06:23 +0100 [thread overview]
Message-ID: <20160401150623.GN32728@redhat.com> (raw)
In-Reply-To: <20160401145819.GA25490@morn.lan>
On Fri, Apr 01, 2016 at 10:58:19AM -0400, Kevin O'Connor wrote:
> On Fri, Apr 01, 2016 at 09:44:56AM +0100, Richard W.M. Jones wrote:
> > On Fri, Apr 01, 2016 at 10:24:37AM +0200, Paolo Bonzini wrote:
> > > On 01/04/2016 10:14, Richard W.M. Jones wrote:
> > > > Found it: only CONFIG_MPTABLE=y was necessary. It boots with:
> > > >
> > > > # CONFIG_PIRTABLE is not set
> > > > CONFIG_MPTABLE=y
> > > > # CONFIG_SMBIOS is not set
> > > > # CONFIG_ACPI is not set
> > >
> > > If you add all three it should not give any slowdown and will provide
> > > full hardware features to the kernel. qboot does ACPI and PCI bus
> > > assignment (it doesn't do SMBIOS because I got bored debugging it. :))
> >
> > Enabling all 4 adds about 2ms.
>
> CONFIG_SMBIOS and CONFIG_ACPI only control the legacy internal bios
> tables. One would disable CONFIG_FW_ROMFILE_LOAD to disable the newer
> ACPI tables; there is no config option currently to disable the newer
> smbios tables.
>
> These config names are a bit misleading, so they probably should be
> changed in seabios.
>
> I didn't expect disabling the above options to do anything besides
> reduce the size of the seabios binary, so I'm a bit suprised it saved
> 2ms. Did you have something on your qemu command-line to avoid
> generating acpi/smbios tables?
The standard deviation of that number over 5 runs was 1ms, so I'm
somewhat confident the 2ms is measuring something real. In the grand
scheme of things it doesn't matter at all.
I'm not using any qemu command line options related to acpi or smbios.
Rich.
--
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next prev parent reply other threads:[~2016-04-01 15:06 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-19 20:31 [Qemu-devel] Why is SeaBIOS used with -kernel? Richard W.M. Jones
2016-03-21 7:58 ` Gerd Hoffmann
2016-03-21 8:37 ` Richard W.M. Jones
2016-03-21 9:40 ` Gerd Hoffmann
2016-03-31 9:21 ` Stefan Hajnoczi
2016-03-31 16:22 ` Kevin O'Connor
[not found] ` <20160331221039.GA32728@redhat.com>
2016-03-31 22:17 ` Richard W.M. Jones
2016-03-31 22:44 ` Kevin O'Connor
2016-04-01 7:55 ` Richard W.M. Jones
2016-04-01 8:03 ` Paolo Bonzini
2016-04-01 8:47 ` Richard W.M. Jones
2016-04-01 8:51 ` Paolo Bonzini
2016-04-01 8:57 ` Richard W.M. Jones
2016-04-01 9:05 ` Paolo Bonzini
2016-04-01 8:02 ` Richard W.M. Jones
2016-04-01 8:11 ` Paolo Bonzini
2016-04-01 8:14 ` Richard W.M. Jones
2016-04-01 8:24 ` Paolo Bonzini
2016-04-01 8:44 ` Richard W.M. Jones
2016-04-01 8:47 ` Paolo Bonzini
2016-04-01 8:49 ` Vasiliy Tolstov
2016-04-01 9:16 ` Dr. David Alan Gilbert
2016-04-01 9:18 ` Gerd Hoffmann
2016-04-01 10:17 ` Richard W.M. Jones
2016-04-01 11:07 ` Gerd Hoffmann
2016-04-01 11:11 ` Richard W.M. Jones
2016-04-01 11:20 ` Richard W.M. Jones
2016-04-01 11:21 ` Paolo Bonzini
2016-04-01 11:26 ` Richard W.M. Jones
2016-04-05 4:38 ` Kevin Wolf
2016-04-05 8:04 ` Richard W.M. Jones
2016-04-05 8:11 ` Kevin Wolf
2016-04-05 9:19 ` Richard W.M. Jones
2016-04-05 9:26 ` Kevin Wolf
2016-04-01 11:32 ` Gerd Hoffmann
2016-04-01 11:49 ` Richard W.M. Jones
2016-04-01 15:35 ` Kevin O'Connor
2016-04-01 16:03 ` Paolo Bonzini
2016-04-01 18:41 ` Richard W.M. Jones
2016-04-01 18:59 ` Richard W.M. Jones
2016-04-01 19:04 ` Kevin O'Connor
2016-04-01 19:10 ` Richard W.M. Jones
2016-04-01 19:15 ` Richard W.M. Jones
2016-04-01 19:44 ` Kevin O'Connor
2016-04-01 20:25 ` Richard W.M. Jones
2016-04-01 20:05 ` Kevin O'Connor
2016-04-01 20:46 ` Richard W.M. Jones
2016-04-01 22:25 ` Kevin O'Connor
2016-04-02 7:51 ` Richard W.M. Jones
2016-04-02 5:30 ` Paolo Bonzini
2016-04-01 15:08 ` Kevin O'Connor
2016-04-01 14:58 ` Kevin O'Connor
2016-04-01 15:06 ` Richard W.M. Jones [this message]
2016-04-01 15:14 ` Kevin O'Connor
2016-04-01 8:19 ` Richard W.M. Jones
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