... to process input, instead of inside each smaller operations such as
appending a character or moving the cursor forward.
In other words, before we were doing (oversimplified):
teken_input()
<for each input character>
vtterm_putchar()
VTBUF_LOCK()
VTBUF_UNLOCK()
vtterm_cursor_position()
VTBUF_LOCK()
VTBUF_UNLOCK()
Now, we are doing:
vtterm_pre_input()
VTBUF_LOCK()
teken_input()
<for each input character>
vtterm_putchar()
vtterm_cursor_position()
vtterm_post_input()
VTBUF_UNLOCK()
The situation was even worse when the vtterm_copy() and vtterm_fill()
callbacks were involved.
The new callbacks are:
* struct terminal_class->tc_pre_input()
* struct terminal_class->tc_post_input()
They are called in teken_input(), surrounding the while() loop.
The goal is to improve input processing speed of vt(4). As a benchmark,
here is the time taken to write a text file of 360 000 lines (26 MiB) on
`ttyv0`:
* vt(4), unmodified: 1500 ms
* vt(4), with this patch: 1200 ms
* syscons(4): 700 ms
This is on a Haswell laptop with a GENERIC-NODEBUG kernel.
At the same time, the locking is changed in the vt_flush() function
which is responsible to draw the text on screen. So instead of
(indirectly) using VTBUF_LOCK() just to read and reset the dirty area
of the internal buffer, the lock is held for about the entire function,
including the drawing part.
The change is mostly visible while content is scrolling fast: before,
lines could appear garbled while scrolling because the internal buffer
was accessed without locks (once the scrolling was finished, the output
was correct). Now, the scrolling appears correct.
In the end, the locking model is closer to what syscons(4) does.
Differential Revision: https://reviews.freebsd.org/D15302
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
The {powerpc,powerpc64,sparc64} LINT kernel builds fail with this error:
sys/dev/vt/vt_buf.c:198: warning: 'vtbuf_htw' defined but not used
Move vtbuf_htw() inside the '#if SC_NO_CUTPASTE' block where it belongs, and
put it in the proper order.
This fixes the immedate issue w/ vt(4), but all three then fail on different
issues.
Reviewed by: emaste
A new terminal_set_cursor() is added: it wraps the existing
teken_set_cursor() function.
In vtbuf_grow(), the cursor position is adjusted at the end of the
function. In vt_change_font(), we call terminal_set_cursor() just after
terminal_set_winsize_blank(), while the terminal is mute.
This fixes a bug where, after loading a kernel video driver which
increases the terminal window size, the cursor remains at its old
position, in other words, in the middle of the display content.
PR: 194421
MFC after: 1 week
It's now possible to scroll up the 500 hard-coded lines of history, not
just a fraction of them. For instance, one can reach the top of the boot
process.
Sometimes, when scrolling or when changing the screen size (by changing
the font or loading a KMS driver for instance), one could see the
history cycling (old content appeared below latest lines). This is
fixed.
Now, when the resolution changes are more lines can be shown, the
displayed area is adjusted so that, if the screen was filled with
content before, it's filled with content after as well: more history
is visible, instead of having blank lines below the previously visible
content.
MFC after: 3 days
... not just the visible part.
This fixes a bug where, when switching from eg. vt_vga to vt_fb (ie. the
resolution goes up), the originally hidden, uninitialized area of the
buffer is displayed on the screen. This leads to a missing text cursor
when it's over an unitialized area.
This was also visible when selecting text: the uninitialized area was
not highlighted.
Internally, this area was zeroed: characters were all 0x00000000,
meaning the foreground and background color was black. Now, everything
is filled with a space with a gray foreground color, like the visible
area.
While here, remove the check for the mute flag and always use
TERMINAL_NORM_ATTR as the character attribute (ie. gray foreground,
black background).
MFC after: 1 week
In several functions, vtbuf_putchar() in particular, the lock on vtbuf
is acquired twice:
1. once by the said functions;
2. once in vtbuf_dirty().
Now, vtbuf_dirty_locked() and vtbuf_dirty_cell_locked() allow to
acquire that lock only once.
This improves the input speed of vt(4). To measure the gain, a
50,000-lines file was displayed on the console using cat(1). The time
taken by cat(1) is reported below:
o On amd64, with vt_vga:
- before: 1.0"
- after: 0.5"
o On sparc64, with creator_vt:
- before: 13.6"
- after: 10.5"
MFC after: 1 week
implement options TERMINAL_{KERN,NORM}_ATTR. These are aliased to
SC_{KERNEL_CONS,NORM}_ATTR and like these latter, allow to change the
default colors of normal and kernel text respectively.
Note on the naming: Although affecting the output of vt(4), technically
kern/subr_terminal.c is primarily concerned with changing default colors
so it would be inconsistent to term these options VT_{KERN,NORM}_ATTR.
Actually, if the architecture and abstraction of terminal+teken+vt would
be perfect, dev/vt/* wouldn't be touched by this commit at all.
Reviewed by: emaste
MFC after: 3 days
Sponsored by: Bally Wulff Games & Entertainment GmbH
vt_grow may be called with a new size that's larger than previous but
does not require reallocation - for example, when the number of columns
is the same and new number of rows is less than the history size.
Prior to this change we would fail to update vb_scr_size, and then hit
a KASSERT when trying to write to the newly visible rows.
Sponsored by: The FreeBSD Foundation
