Re: textdumps are too slow

On Fri, Apr 7, 2023 at 12:08 PM Warner Losh <imp@bsdimp.com> wrote:
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> On Fri, Apr 7, 2023 at 6:20 AM Poul-Henning Kamp <phk@phk.freebsd.dk> wrote:
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>> --------
>> Alan Somers writes:
>> > On Fri, Apr 7, 2023 at 2:22=E2=80=AFAM Poul-Henning Kamp <phk@phk.freebsd.dk> wrote:
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>> > > I would expect them to be limited by the serial console speed before
>> > > the video system speed ?
>> >
>> > That was my first guess, too.  But my serial console is 115200 baud,
>> > which is faster than the low performance server grade video card.
>>
>> Ok, that must truly be sucky hardware...
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> That's 10x slower than 1990s era VGA cards then... 115200 is 11k characters a second,
> and FreeBSD on 1990s era VGA cards was in excess of 1MB/s, faster if not a pure ISA
> card... Video hardware that's slower than *THAT* likely indicates a big big problem in
> our video stack.
>
> Warner

While I'm logged into the video terminal in a normal login session, I
measure about 28M characters/second.  So maybe the slow speed is due
to something inefficient in ddb(4).