Bug#755739: VGA-mode newcons very slow
> On 22/07/14 19:58, Jan Henke wrote:
>> I am experiencing a strange problem with the current kFreeBSD weekly
>> image. Whenever the system is writing to the screen in text mode (e.g.
>> directly after selecting one entry in GRUB: "Copyright....") you can
>> literally watch every single character printed to the screen one after
>> the other. So it takes ages before you even get into the Debian
>> installer. I am running inside a Hyper-V VM. I have double checked
>> against FreeBSD (the upstream one), which does not show this behaviour.
Jan, can you clarify which upstream FreeBSD version and console you
compared against? I suspect you had (text-mode) syscons in the
FreeBSD VM. If graphics-mode vt(4) has wildly different performance
between Debian kFreeBSD and FreeBSD then something very strange is
going on, and we'll want to track it down.
In both FreeBSD-CURRENT and stable/10 we can now switch between
syscons and vt at boot time, with sc as the default. The console and
mode can be set via loader tunables:
syscons, text mode:
kern.vty=sc
vt(4), text mode:
kern.vty=vt
hw.vga.textmode=1
vt(4), graphics mode:
kern.vty=vt
hw.vga.textmode=0
It should be possible to start with hw.vga.textmode=1 and then have
i915kms take over once X starts, giving graphics-mode consoles from
that point on.
On 22 July 2014 17:12, Steven Chamberlain <steven@pyro.eu.org> wrote:
>
> I've seen the exact same thing under plain Qemu: newcons in VGA mode
> seems very slow (but not as serious as you describe in Hyper-V).
Can you quantify "very slow?" I've been testing vt(4) in QEMU on my
FreeBSD host (so no KVM involved), and it's acceptably performant on
my 8-core i7-3770 desktop.
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