From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Ihor Radchenko <yantar92@posteo.net>
Cc: emacs-devel@gnu.org
Subject: Re: Markers in a gap array
Date: Thu, 04 Jul 2024 18:24:47 -0400 [thread overview]
Message-ID: <jwvikxk24d3.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <jwvzfqx0wde.fsf-monnier+emacs@gnu.org> (Stefan Monnier's message of "Thu, 04 Jul 2024 16:11:28 -0400")
BTW, I just pushed to `scratch/gl-state-bytepos` an orthogonal patch
which intends to reduce the use of `bytepos_to_charpos` by changing
the `gl_state` cache so it keeps track of the byteposition of the
boundaries of the current "chunk of `syntax-table` property".
This way RE_UPDATE_SYNTAX_TABLE can take a bytepos rather than an charpos
and convert it to charpos only when moving into a different "chunk of
`syntax-table` property".
On that previous benchmark, it works wonderfully (the implementation of
markers has basically no impact any more in that benchmark):
| test | non-gc avg (s) | gc avg (s) | gcs avg | tot avg (s) | tot avg err (s) |
|------------------------+----------------+------------+---------+-------------+-----------------|
| bytechar | 6.25 | 0.00 | 0 | 6.25 | 0.85 |
| bytechar-100k | 6.41 | 0.00 | 0 | 6.41 | 0.65 |
| bytechar-100k-nolookup | 6.61 | 0.00 | 0 | 6.61 | 0.17 |
| bytechar-100k-random | 8.63 | 0.00 | 0 | 8.63 | 0.06 |
| bytechar-100k-rev | 7.64 | 0.00 | 0 | 7.64 | 1.48 |
| bytechar-10k-random | 6.79 | 0.00 | 0 | 6.79 | 0.10 |
| bytechar-1k-random | 6.64 | 0.00 | 0 | 6.64 | 0.15 |
| bytechar-nolookup | 6.63 | 0.00 | 0 | 6.63 | 0.23 |
|------------------------+----------------+------------+---------+-------------+-----------------|
| total | 55.61 | 0.00 | 0 | 55.61 | 1.86 |
Of course, that's the ideal case: that buffer has no `syntax-table` text
properties, so there's only one chunk. In buffers with many uses of the
`syntax-table` text property, the patch may end up slowing things down
because the update from one chunk to another requires not just
a bytepos->charpos but also two additional charpos->bytepos conversions.
Still, I suspect it will usually be beneficial (the cost of going from
one chunk to another is itself significant so the extra charpos->bytepos
conversions should not slow it down unduly).
The patch has a significant FIXME that needs invesitgating (it passes
all tests, but I'm not sure it's doing the right thing).
Stefan
next prev parent reply other threads:[~2024-07-04 22:24 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-04 4:59 Markers in a gap array Stefan Monnier
2024-07-04 10:24 ` Ihor Radchenko
2024-07-04 13:16 ` Stefan Monnier
2024-07-04 14:30 ` Ihor Radchenko
2024-07-04 20:11 ` Stefan Monnier
2024-07-04 20:34 ` Pip Cet
2024-07-04 20:42 ` Stefan Monnier
2024-07-17 16:48 ` Helmut Eller
2024-07-18 20:46 ` Stefan Monnier
2024-07-26 19:48 ` Helmut Eller
2024-08-05 19:54 ` MPS: marker-vector (was: Markers in a gap array) Helmut Eller
2024-08-05 21:14 ` MPS: marker-vector Pip Cet
2024-08-06 6:28 ` Helmut Eller
2024-08-06 6:51 ` Gerd Möllmann
2024-08-06 14:36 ` Pip Cet
2024-08-06 16:15 ` Helmut Eller
2024-08-06 3:59 ` Gerd Möllmann
2024-08-06 6:02 ` Helmut Eller
2024-07-04 22:24 ` Stefan Monnier [this message]
2024-07-07 12:31 ` Markers in a gap array Ihor Radchenko
2024-07-07 13:09 ` Konstantin Kharlamov
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