From: Laszlo Ersek <lersek@redhat.com>
To: A Z <adam@zegelin.com>, edk2-devel@lists.01.org
Subject: Re: [OVMF+VIFO+QEMU] Large VM RAM allocation = Long Boot Times
Date: Thu, 15 Nov 2018 11:39:32 +0100 [thread overview]
Message-ID: <7243ddb2-fc84-0598-6713-da5cd8a8d9c5@redhat.com> (raw)
In-Reply-To: <CAP2KGUnz+vLfSX9+9bgBohKhJ-JxZPQY253M3tPX=Zn3KUzdMg@mail.gmail.com>
On 11/15/18 06:58, A Z wrote:
> This is an issue that involves a combination of different software
> packages, so my apologies in advance if this is the wrong list to post on.
>
> I'm experiencing terrible boot times when I assign a large amount of RAM to
> a VM when used in combination with VIFO/PCI-passthrough.
>
> On a VM with a Nvidia GTX 970 + USB controller and 24GiB of RAM assigned,
> the time to the TianoCore splash screen is ~5 minutes. It's then ~30
> seconds before Windows 10 begins to boot (spinning dots). During this time,
> the QEMU CPU core threads are 100% busy.
>
> According to `perf`, the QMU CPU core threads are spending most of their
> time waiting on a spinlock over kvm->mmu_lock that's created by
> kvm_zap_gfn_range.
>
> I'm fairly certain that ~1 year ago (if not longer) the same configuration
> didn't take this long to boot.
I see you posted this to vfio-users as well -- that would have been my
recommendation anyway. I'll follow up there briefly.
Thanks
Laszlo
prev parent reply other threads:[~2018-11-15 10:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-15 5:58 [OVMF+VIFO+QEMU] Large VM RAM allocation = Long Boot Times A Z
2018-11-15 10:34 ` Philippe Mathieu-Daudé
2018-11-15 10:39 ` Laszlo Ersek [this message]
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