On Fri, Apr 7, 2023, 4:07 PM Rodney W. Grimes <freebsd-...@gndrsh.dnsmgr.net> wrote:
> > On Fri, Apr 7, 2023 at 12:08?PM Warner Losh <i...@bsdimp.com> wrote: > > > > > > > > > > > > On Fri, Apr 7, 2023 at 6:20?AM Poul-Henning Kamp <p...@phk.freebsd.dk> > wrote: > > >> > > >> -------- > > >> Alan Somers writes: > > >> > On Fri, Apr 7, 2023 at 2:22=E2=80=AFAM Poul-Henning Kamp < > p...@phk.freebsd.dk> wrote: > > >> > > >> > > 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... > > > > > > > > > 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). > > Do you mean to a physically connected vga display and usb/ps2 connected > keyboard, or do you mean a serially connected video terminal, or something > else like a console created by a BMC? > > One other thing that could be at issue is a console redirection via > serial port, that can make "VGA device" performance appear abismal. > > > -- > Rod Grimes > rgri...@freebsd.org It's a BMC video console. I'm also using a BMC serial port, but during panic I measured the serial port as faster than the video port. >
