Date: Fri, 7 Apr 2023 16:17:09 -0600 From: alan somers <asomers@gmail.com> To: "Rodney W. Grimes" <freebsd-rwg@gndrsh.dnsmgr.net> Cc: Alan Somers <asomers@freebsd.org>, Warner Losh <imp@bsdimp.com>, Poul-Henning Kamp <phk@phk.freebsd.dk>, FreeBSD CURRENT <freebsd-current@freebsd.org> Subject: Re: textdumps are too slow Message-ID: <CAOtMX2joLPsbDawpKD1L95L3m6tuTuLsN%2BC6d0oHzQ3stk4o1Q@mail.gmail.com> In-Reply-To: <202304072207.337M7Dim016129@gndrsh.dnsmgr.net> References: <CAOtMX2gbpy4AXXScbEsc5ho3cv7M%2BT8aVuwyak-PeSdzPqOd_g@mail.gmail.com> <202304072207.337M7Dim016129@gndrsh.dnsmgr.net>
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[-- Attachment #1 --] On Fri, Apr 7, 2023, 4:07 PM Rodney W. Grimes <freebsd-rwg@gndrsh.dnsmgr.net> wrote: > > On Fri, Apr 7, 2023 at 12:08?PM Warner Losh <imp@bsdimp.com> wrote: > > > > > > > > > > > > On Fri, Apr 7, 2023 at 6:20?AM Poul-Henning Kamp <phk@phk.freebsd.dk> > wrote: > > >> > > >> -------- > > >> Alan Somers writes: > > >> > On Fri, Apr 7, 2023 at 2:22=E2=80=AFAM Poul-Henning Kamp < > phk@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 > rgrimes@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. > [-- Attachment #2 --] <div dir="auto"><div><br><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Apr 7, 2023, 4:07 PM Rodney W. Grimes <<a href="mailto:freebsd-rwg@gndrsh.dnsmgr.net">freebsd-rwg@gndrsh.dnsmgr.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">> On Fri, Apr 7, 2023 at 12:08?PM Warner Losh <<a href="mailto:imp@bsdimp.com" target="_blank" rel="noreferrer">imp@bsdimp.com</a>> wrote:<br> > ><br> > ><br> > ><br> > > On Fri, Apr 7, 2023 at 6:20?AM Poul-Henning Kamp <<a href="mailto:phk@phk.freebsd.dk" target="_blank" rel="noreferrer">phk@phk.freebsd.dk</a>> wrote:<br> > >><br> > >> --------<br> > >> Alan Somers writes:<br> > >> > On Fri, Apr 7, 2023 at 2:22=E2=80=AFAM Poul-Henning Kamp <<a href="mailto:phk@phk.freebsd.dk" target="_blank" rel="noreferrer">phk@phk.freebsd.dk</a>> wrote:<br> > >><br> > >> > > I would expect them to be limited by the serial console speed before<br> > >> > > the video system speed ?<br> > >> ><br> > >> > That was my first guess, too. But my serial console is 115200 baud,<br> > >> > which is faster than the low performance server grade video card.<br> > >><br> > >> Ok, that must truly be sucky hardware...<br> > ><br> > ><br> > > That's 10x slower than 1990s era VGA cards then... 115200 is 11k characters a second,<br> > > and FreeBSD on 1990s era VGA cards was in excess of 1MB/s, faster if not a pure ISA<br> > > card... Video hardware that's slower than *THAT* likely indicates a big big problem in<br> > > our video stack.<br> > ><br> > > Warner<br> > <br> > While I'm logged into the video terminal in a normal login session, I<br> > measure about 28M characters/second. So maybe the slow speed is due<br> > to something inefficient in ddb(4).<br> <br> Do you mean to a physically connected vga display and usb/ps2 connected<br> keyboard, or do you mean a serially connected video terminal, or something<br> else like a console created by a BMC?<br> <br> One other thing that could be at issue is a console redirection via<br> serial port, that can make "VGA device" performance appear abismal.<br> <br> <br> -- <br> Rod Grimes <a href="mailto:rgrimes@freebsd.org" target="_blank" rel="noreferrer">rgrimes@freebsd.org</a></blockquote></div></div><div dir="auto"><br></div><div dir="auto">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.</div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br> </blockquote></div></div></div>help
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