From: "Daniel P. Berrangé" <berrange@redhat.com>
To: gokul cg <gokuljnpr@gmail.com>
Cc: qemu-devel@nongnu.org, qemu-discuss@nongnu.org
Subject: Re: X86: Abnormal variation in Freebsd VM launch time w.r.t freebsd guest config
Date: Tue, 7 Apr 2020 10:22:46 +0100 [thread overview]
Message-ID: <20200407092246.GC843246@redhat.com> (raw)
In-Reply-To: <CAFP4jM8RpUXCxUN_J-Enkx_LZU67Vbn45voGBLHH3CG0ELi2Vg@mail.gmail.com>
On Tue, Apr 07, 2020 at 09:59:59AM +0530, gokul cg wrote:
> Hi Team,
>
> We are observing abnormal variation in VM launch time w.r.t guest config.
>
> A simple VM(2gb ram no passthrough device) creation takes usually 6sec
> (Time from execution of 'virsh create guest.xml to get print "Welcome to
> FreeBSD"' ),but when we add a USB passthrough device launch time increased
> to 18-19 sec and further increased to 39-44sec when we have increased guest
> ram to 48Gb.
snip.
> Note : 1) This we have seen with legacy pci passthrough device not with
> vfio. And we have not noticed any perfoance impact other than qemu-init/vm
> laucn time .
Legacy pci passthrough support was deleted way back to 2017, and we had
deprecated it for 2 years before then, in favour of VFIO.
> Any suggestions to improve launch time with legacy passthrough ?
Just stop using legacy PCI assignment. VFIO has been the recommended
impl for 5+ years now.
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
parent reply other threads:[~2020-04-07 9:26 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <CAFP4jM8RpUXCxUN_J-Enkx_LZU67Vbn45voGBLHH3CG0ELi2Vg@mail.gmail.com>]
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=20200407092246.GC843246@redhat.com \
--to=berrange@redhat.com \
--cc=gokuljnpr@gmail.com \
--cc=qemu-devel@nongnu.org \
--cc=qemu-discuss@nongnu.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).