From: Phillip Susi <phill@thesusis.net>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Pavel Machek <pavel@ucw.cz>, Randy Dunlap <rdunlap@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
"linux-doc\@vger.kernel.org" <linux-doc@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
Linux Fbdev development list <linux-fbdev@vger.kernel.org>
Subject: Re: fbcon: remove soft scrollback code (missing Doc. patch)
Date: Tue, 02 Feb 2021 10:13:14 -0500 [thread overview]
Message-ID: <87wnvqts9g.fsf@vps.thesusis.net> (raw)
In-Reply-To: <YBlfKgQ1laQLFqpW@phenom.ffwll.local>
Daniel Vetter writes:
> Just a quick comment on this: Since most framebuffers are write-combining,
> and reads from that tend to be ~3 orders of magnitude slower than writes
> (at least on the pile of machines I looked at here, there's big
> differences, and some special streaming cpu instructions to make the
> reading side not so slow).
>
> So scrolling by copying tends to be significantly slower than just
> redrawing everything.
I know this was the case years ago with AGP as iirc, it doubled ( 4x, 8x
) the PCI clock rate but only for writes wasn't it? I thought this was
no longer an issue with PCIe, but if it is, then I guess I'll go ahead
with cleaning up the dead code and having it re-render with the larger
text buffer.
WARNING: multiple messages have this Message-ID (diff)
From: Phillip Susi <phill@thesusis.net>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: Linux Fbdev development list <linux-fbdev@vger.kernel.org>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Randy Dunlap <rdunlap@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Pavel Machek <pavel@ucw.cz>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: fbcon: remove soft scrollback code (missing Doc. patch)
Date: Tue, 02 Feb 2021 10:13:14 -0500 [thread overview]
Message-ID: <87wnvqts9g.fsf@vps.thesusis.net> (raw)
In-Reply-To: <YBlfKgQ1laQLFqpW@phenom.ffwll.local>
Daniel Vetter writes:
> Just a quick comment on this: Since most framebuffers are write-combining,
> and reads from that tend to be ~3 orders of magnitude slower than writes
> (at least on the pile of machines I looked at here, there's big
> differences, and some special streaming cpu instructions to make the
> reading side not so slow).
>
> So scrolling by copying tends to be significantly slower than just
> redrawing everything.
I know this was the case years ago with AGP as iirc, it doubled ( 4x, 8x
) the PCI clock rate but only for writes wasn't it? I thought this was
no longer an issue with PCIe, but if it is, then I guess I'll go ahead
with cleaning up the dead code and having it re-render with the larger
text buffer.
_______________________________________________
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dri-devel@lists.freedesktop.org
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next prev parent reply other threads:[~2021-02-02 15:25 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <git-mailbomb-linux-master-50145474f6ef4a9c19205b173da6264a644c7489@kernel.org>
2020-09-15 1:18 ` fbcon: remove soft scrollback code (missing Doc. patch) Randy Dunlap
2020-09-15 1:28 ` Bhaskar Chowdhury
2020-09-15 1:30 ` Linus Torvalds
2020-09-15 1:34 ` Randy Dunlap
2020-09-15 1:28 ` Linus Torvalds
2020-09-16 20:54 ` Pavel Machek
2020-09-18 10:27 ` Adam Borowski
2020-09-30 21:29 ` Maciej W. Rozycki
2021-01-08 19:01 ` Phillip Susi
2021-01-08 23:11 ` Linus Torvalds
2021-01-12 15:00 ` Phillip Susi
2021-01-12 16:11 ` Greg Kroah-Hartman
2021-01-12 15:57 ` Daniel Vetter
2021-01-12 15:57 ` Daniel Vetter
2021-01-14 15:56 ` Geert Uytterhoeven
2021-01-14 15:56 ` Geert Uytterhoeven
2021-01-14 16:11 ` Daniel Vetter
2021-01-14 16:11 ` Daniel Vetter
2021-01-15 8:06 ` Geert Uytterhoeven
2021-01-15 8:06 ` Geert Uytterhoeven
2021-02-03 8:03 ` Thomas Zimmermann
2021-02-03 8:03 ` Thomas Zimmermann
2021-01-22 18:55 ` Phillip Susi
2021-01-22 18:55 ` Phillip Susi
2021-01-25 15:39 ` Geert Uytterhoeven
2021-01-25 15:39 ` Geert Uytterhoeven
2021-02-02 14:18 ` Daniel Vetter
2021-02-02 14:18 ` Daniel Vetter
2021-02-02 15:13 ` Phillip Susi [this message]
2021-02-02 15:13 ` Phillip Susi
2021-02-02 15:23 ` Daniel Vetter
2021-02-02 15:23 ` Daniel Vetter
2021-01-14 17:43 ` fbcon: remove soft scrollback code Alan Mackenzie
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