[Libreoffice-bugs] [Bug 48932] New: EDITING: Writer 3.5.2 slow typing in large documents

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=48932

             Bug #: 48932
           Summary: EDITING: Writer 3.5.2 slow typing in large documents
    Classification: Unclassified
           Product: LibreOffice
           Version: LibO 3.5.2 Release
          Platform: x86-64 (AMD64)
        OS/Version: Windows (All)
            Status: UNCONFIRMED
          Severity: critical
          Priority: medium
         Component: Writer
        AssignedTo: libreoffice-bugs at lists.freedesktop.org
        ReportedBy: jamee.mikell at gmail.com


** Possibly Related To **

I believe this bug is related to bug 48011, but I am reporting for Windows and
3.5.2 where 48011 is Linux and 3.5.0/3.5.1. (Maybe should be all 3.5.x, all
platforms???) 48011 is focused on text in tables where this bug is focused on
non-table text. (Maybe it's any text???) 48011 is critical severity, so I have
set this to the same.

If I should post this against 48011, please let me know and I will. I wasn't
sure if that was proper and didn't want to step on the other bug.

** System **

Win7 64-bit, Core i5-480M, 8GB RAM, LO 3.5.2 (release), Language Tool 1.7
installed (disabling doesn't make a difference), only English dictionaries
installed.

** Problem Description **

Open 700+ page document in Writer 3.5.2. After 2-3 seconds, soffice.bin process
goes to 25% CPU (i.e., 100% of 1 core) as reported by Windows Task Manager for
about 2m 15s (timed it). During this CPU spike, Writer is useless because
response to typing is so S-L-O-W. By slow typing, I mean rendering, "This is a
test of typing in LibreOffice 3.5.2" took 10+ seconds longer than it took me to
type it. I originally thought this was a file open problem, but further testing
revealed this is not the case (more about that shortly).

Writer 3.4.3 (running same version of Language Tool) opens the same document
and is ready to go. No slow typing.

** Additional Observations **

The document is plain text. Basic margins and a header (page number). No
images, tables, bullets, etc. Portrait orientation (so likely not bug 48235).
ODT format.

Opening a much smaller document in 3.5.2., I see a short 25% CPU spike for <5
seconds, so the initial spike time seems to be related to document size.

3.5.2 does not seem to be counting pages, etc. It has the right page count as
soon as the document displays on screen and that count never changes.

3.5.2 does not seem to be spell-checking. I see red wavy underlines before the
CPU spike. I can jump to the end of the document before the spike starts and
see red wavy underlines there. Likewise, a fast set of page downs before the
spike shows red wavy underlines. I also tested with 300+ page lorem ipsum,
which throws red wavy underlines under every word, so it's really obvious it
had identified misspelled words. CPU was still spiked at 25% (1 full core) long
after.

Further testing showed that 3.5.2's issue is not limited to file open. After
the file open settled down to 0% CPU, typing new text spiked the CPU core (CPU
= 25%) every time. Slow typing as described above. CPU stayed spiked until
Writer finished catching up with typing.

I have reverted to 3.4.3 (had the install still, rather than download 3.4.6)
and can report 3.4.3 performance for comparison. 

3.4.3 also spikes the CPU to 25% on file open (100% of 1 core) for a couple of
minutes (didn't time precisely). But 3.4.3. doesn't have the slow typing
issue--ever. I can type immediately and Writer 3.4.3 keeps up with no problems.
After file open settles down, 3.4.3's max CPU while typing new text is 2% in
multiple tests (vs. 3.5.2's 25%).

3.4.3 will occasionally exceed 25% CPU during the file open spike, suggesting
it is using part of a second core. Typing while CPU is 25% after a file open
jumps to 26% CPU and stays there until I stop typing. Occasionally doing
nothing, CPU will go as high as 28%. 3.5.2 never went over 25% (never more than
1 core). Wild guess/theory: Is 3.5.x limited to a single core where 3.4.x was
allowed to use more than one core? I tried 3.5.1 but reverted to 3.4.3 when it
showed similar slow typing behavior. I didn't check CPU use, etc. on 3.5.1, but
since behavior is the same and 48011 describes similar behavior in 3.5.0 and
3.5.1 on Linux, this may be the same issue.

If you need a test document, let me know. I can't post my working document, but
I can use http://www.lipsum.com/ to generate a 10k word lorem ipsum and paste
it multiple times to create a comparable page-count document.

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