High CPU Use When Mouse Scrolling

noibs · Sentinel Joined: Dec 09, 2006 Posts: 22

There's a particular ODT format document (1.2 ODF format version) of mine that's large (275 pages) with many inline graphics objects. The size is 8.5 MB.

Now, whenever I scroll the document a few pages using my mouse scroll wheel, the NeoOffice CPU use exceeds 100% and the scrolling is very slow and uneven. The fans on my MacBook come on almost immediately.

I have a companion document that about the same size with the same number of inline graphics objects that doesn't do this when I scroll.

Any ideas?

noibs · Sentinel Joined: Dec 09, 2006 Posts: 22

Just an update to my original post.

Using the most recent Mac version of Open Office, CPU use when scrolling the same document is between 20% and 30%--still high, but not 100%+ as is the case in NeoOffice. I realize the current version of NeoOffice is based on an older version of Open Office.

pluby · The Architect Joined: Jun 16, 2003 Posts: 11949

Since your document uses a lot less CPU in a newer version of OpenOffice.org than the one NeoOffice uses and OpenOffice.org 3.2.1 has some major performance improvements that are not in NeoOffice's underlying OpenOffice.org 3.1.1 code, the bad news is that you may need the newer OpenOffice.org version to work around this.

Nevertheless, there are some things that you can try changing in your document that might help:

1. Disable spellchecking - When you have spellchecking enabled, NeoOffice spends a lot of CPU spellchecking your entire document while you work. For a 275 page document, that is a lot of work it must do that can be avoided by unclicking the AutoSpellcheck toolbar button.

2. Disable paragraph splitting options - Highlight your entire document by selecting the Edit :: Select All menu and then select the Format :: Paragraph menu. In the dialog that appears, click on the Text Flow tab and make sure that all of the checkboxes in the "Options" section are unchecked. If any of these checkboxes are checked, CPU usage can become very high.

3. Insert manual page breaks - For NeoOffice to determine where to display any text or graphic, it must layout all of the text and graphics preceding it in the document. By inserting manual page breaks every so often throughout the document, in many cases you can significantly cut down how much layout of preceding text that NeoOffice must do.

Hope that helps.

Patrick

noibs · Sentinel Joined: Dec 09, 2006 Posts: 22

Patrick,

Thanks for the suggestions. I don't have auto spell-checking enabled. The document is an Accounting workbook that students use in a course I teach. Everything in the document is assigned some kind of paragraph style. I don't believe that I've enabled any paragraph splitting options but I'll check. Option (3) is out of the question because the workbook is being constantly updated and changed from one semester to the next and I can't afford hard page breaks.

Thanks again.

pluby · The Architect Joined: Jun 16, 2003 Posts: 11949

pluby · The Architect Joined: Jun 16, 2003 Posts: 11949

I have another idea that you can try. Instead of me listing a bunch of things for you to change that may or may not help, I think a better idea would be for you to collect a sample of the NeoOffice application when CPU usage shoots up to 100%.

Hopefully, from such a sample we might be able to identify what specific processing NeoOffice is actually doing that needs 100% CPU so that we can recommend a more specific change to your document.

To collect a sample of the NeoOffice process, following the instructions in this NeoWiki article. I would recommend do steps 1 through 5 in that article and then, when CPU shoots up, immediately switch to the Activity Monitor application and do steps 6 through 8. The faster you can start the sampling (step 6) in the Activity Monitor application, the better the sample will be for us.

Patrick

noibs · Sentinel Joined: Dec 09, 2006 Posts: 22

Patrick,

I opened my large document and waited for things to settle down. I went to the middle of the document and began scrolling with my mouse scroll wheel. That was all. Activity Monitor showed about 103% CPU use. I think I got a good, quick sample; however, within 3 seconds, CPU use by NeoOffice was back to 2% to 3%.

I attached a text file with the sample. I'm going to be traveling the next few days (with a Dell Mini 10v hackintosh), so I won't be able to do anything more for a while with respect to this issue. Hopefully the sample will give you some answers.

What's ironic about this whole thing is that my #1 reason for using NeoOffice instead of OpenOffice is the problem OpenOffice has with mouse wheel scrolling on Macs. With scroll speed set as fast as possible within OSX, one complete revolution of a mouse scroll wheel (I've tried several) moves an OpenOffice writer document about a half page--way too slow. Therefore, when I use OpenOffice I use the shareware Steermouse driver that allows for highly custom scroll wheel speeds for each application.

With NeoOffice, the mouse wheel scrolling speed is about the same as it is for other Mac apps. Therefore, whatever you are doing in NeoOffice to change scroll wheel behavior (as compared to stock OpenOffice) might be contributing my my CPU saturation when scrolling.

Thanks again.

pluby · The Architect Joined: Jun 16, 2003 Posts: 11949

noibs · Sentinel Joined: Dec 09, 2006 Posts: 22

Patrick,

I'm away from home (and will be for a while), but I can still answer your questions.

1. Hardware: Mid 2007 Macbook w/ 2.16ghz Core 2 Duo w/4MB cache. 3GB of addressable RAM (actually has 4GB of physical RAM). 320GB hard drive, 80% free space.
2. Neooffice version and patch. Latest versions of both. I always update to the most recent patch and I've been using the latest version of NeoOffice since it was released.
3. The primary font used in 99.99% of my large document I was scrolling is Times New Roman in various sizes. All text in the document is assigned a paragraph style. The footer contains a field that corresponds to Heading 1 (chapter name). The footer also contains a self-generated page number.

The noteworthy thing about the document itself is that it contains perhaps 125 in-line graphics images. These are mostly pieces of Calc (spreadsheet) documents that were copied to the clipboard and then pasted into my Writer document as GDI Metafile objects. Some are quite complex and cover most of a page. Remember that this is an Accounting book.

I would like to email you a copy of the document; however, I won't be home for a while and don't have a current version with me. Also, it's 8.5mb in size.

Thanks.

pluby · The Architect Joined: Jun 16, 2003 Posts: 11949

noibs · Sentinel Joined: Dec 09, 2006 Posts: 22

Patrick,

Two things:

1. I'm running 10.6.3. I upgraded from 10.5.8 to 10.6.3 about six weeks ago. I can't be sure, but I don't believe I had this problem under 10.5.x.

2. I'm on vacation and don't have access to the file. A week from today, I'll put the file on a custom Mobile Me Web page and put the link here.

I normally would have a copy of the file with me, but some things got messed up as we were trying to leave and it didn't get copied to my Dell hackintosh.

pluby · The Architect Joined: Jun 16, 2003 Posts: 11949

noibs · Sentinel Joined: Dec 09, 2006 Posts: 22

Patrick,

I've sent you a personal message containing an address where you can download my odt file that leads to high CPU use when mouse scrolling.

Note that when this happens I'm not using my custom Steermouse driver. I'm only using the standard Apple mouse driver under 10.6.3. I've only installed Steermouse when I've used OpenOffice.

For the first 10 seconds or so after opening NeoOffice and doing fast mouse scrolling, CPU use in Activity Monitor will not peak. After that time, it does peak and will then peak again as soon as I start fast scrolling.

My standard mouse is a fairly new Kensington Mouse in a Box that has two left-right buttons plus a scroll wheel (that also has a button). The scrolling speed in the mouse system preferences under 10.6.3 is set to the fastest level. I do NOT use the Kensington mouse software.

I'm beginning to wonder if my mouse is part of the problem. Even though my Mouse in a Box model is the newest version of this mouse, the basic mouse has been around for a long time. I have to set the scrolling speed in 10.6.3's system preferences to the fastest possible level in order to get just acceptable scroll wheel responsiveness in NeoOffice and other applications.

Thanks.

pluby · The Architect Joined: Jun 16, 2003 Posts: 11949

I download your .odt file successfully so I will see if I can reproduce the problem that you see over the next day.

I will post again when I have some results to report.

Patrick

pluby · The Architect Joined: Jun 16, 2003 Posts: 11949

I have been able to reproduce the 100% CPU usage with your document. The good news is that I do not think that it is caused by your mouse driver because I was able to reproduce it without touching the mouse wheel. I only needed to click on the vertical scroll bar repeatedly to trigger to the problem.

I also was able to use Apple's "Shark" development tool to find out which code is consuming so much CPU and it is the font glyph size calculation code. In rare cases, NeoOffice's underlying OpenOffice.org code will query not only how many pixels a word requires for a given font and font size, but it will query the exactly dimensions of each of the glyphs in a word.

Querying glyph dimensions is much more CPU intensive than measuring the length of a word so this is where the problem is so clearly the NeoOffice glyph querying code is less efficient than the equivalent OpenOffice.org code so I will look at our code and see if there are any speed bottlenecks in our code that we can eliminate.

Patrick