[Libguestfs] [PATCH v2 0/7] tests/qemu: Add program for tracing and analyzing boot times.

Török Edwin edwin+guestfs at etorok.net
Sun Mar 20 15:28:05 UTC 2016

On 03/20/2016 14:30, Richard W.M. Jones wrote:
> v1 was here:
>   https://www.redhat.com/archives/libguestfs/2016-March/thread.html#00157

Thanks, this is much better than looking at 'ts -i' output.

BTW I have use 'git am' to apply them to latest git HEAD and try it.
Is this the preferred way, or is there a git branch/repo somewhere that I missed which would already have these applied?

> Not running the 'hwclock' command reduces boot times considerably.
> However I'm not sure if it is safe.  See the question I posted on
> qemu-devel:
>   http://thread.gmane.org/gmane.comp.emulators.qemu/402194
> At the moment, about 50% of the time is consumed by SeaBIOS.  Of this,
> about ⅓rd is SGABIOS (it contains a useless ¼s sleep waiting for a
> keypress ... ffs!)

Ah, I didn't have sgabios installed, and it complained it couldn't find an event (qemu:overhead?).
Installed it and I got similar results to yours, the largest overhead is BIOS: https://gist.github.com/anonymous/37cfb3d4eb3d3a1c86b2

Thought to try booting a Xen PV domain for comparison, but AFAICT libguestfs doesn't support LIBGUESTFS_BACKEND=libvirt:xen:///

>, and the other ⅔rds is something else in SeaBIOS.
> Simply removing SGABIOS improves boot times to below 2s, but at a cost
> that we cannot see any messages from SeaBIOS so further measurement
> and therefore improvement becomes impossible.  I'm going to try to fix
> SeaBIOS/SGABIOS first.  See also:
>   http://thread.gmane.org/gmane.comp.emulators.qemu/402196

Nice, this would benefit booting regular VMs too, not just libguestfs appliances, right?

Best regards,
Edwin Török | Co-founder and Lead Developer

Skylable open-source object storage: reliable, fast, secure

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