Martin Vermeer wrote:
On Fri, Feb 03, 2006 at 04:02:41PM +0100, Helge Hafting wrote:
There is a strange performance problem when displaying a lyx that is
running on another machine. (ADSL connection)
How fast is your ADSL? And is it the same both ways (A = Asymmetric)?
It is a nice fast connection. It was something like 3000/768 although
they keep increasing this in little chunks to stay ahead of competition.
Most editing operations are fine (writing text, deleting, scrolling)
there is no bandwith problem. But press enter so that a
new paragraph is created. This operation takes 6 seconds in my case!
The network gets busy for the 6 seconds, I have no idea what happens.
It is not a case of too much work scrolling half of the display, for simply
writing so much text that the existing paragraph breaks into
several lines is not a problem at all. Also, grabbing the
scrollbar and rolling through the document is fine.
That is weird... if it was about whole-screen refresh, these operations
should be slow too.
I tested the userguide, no problems there. Further testing shows that
it is related to images. I have some high resolution images - of course
I expect those to be slow. But the slowness happen even in cases where
images aren't on screen. Typical case:
The document have some long bulleted lists, containing some figure floats
with big images. They don't have to be on screen though - split a paragraph
before or after the images, and it'll be slow as long
as it is the same bullet list that contain images somewhere.
Perhaps the explanation here is that the graphichs are "close enough"
that lyx transfer them just in case?
But strangely enough, splitting a paragraph is much worse than simply
adding in-paragraph lines (ctrl+enter).
I can push an image around with ctrl+enter, and it'll all be
as snappy as having the file locally. The graphichs bounce around on
the screen,
clearly qt is smart enough to cache it on the xserver somehow. But split a
paragraph (or add/remove one entirely) and slowness happens.
Now, some remote graphichs related delays are expected, and not a reason to
hold up 1.4.0. But I think paragraph manipulations must be doing something
unnecessary, moving the graphics around is clearly not the problem here.
There is lots of network traffic througout the delay period.
The delays can be long, splitting a paragraph close to a bigger image
gave me a 24 seconds break!
It is just these operations that take everlasting 6 seconds:
* Press enter to split a paragraph (or create a blank one)
* Press backspace so as to delete a paragraph
boundary, merging two paragraphs
* Let the cursor leave an empty paragraph so lyx auto-destroys it.
* Cutting/pasting an entire paragraph. Cutting/pasting the same amount
if text inside a single bigger paragraph is not a proble,
Clearly, something strange and unnecessary happens over the network
when the number of paragraphs change. And it don't look like something
that can be blamed on qt either.
Just to make sure: same document locally is fast? And are there any
differences between client and server installation (X?) that could
explain this?
Same document locally is fast, on the same xserver that cause
delays when the document is remote. Using the display
on the remote machine for local editing is also fast.
Helge Hafting
