| Title: | DECWINDOWS 26-JAN-89 to 29-NOV-90 |
| Notice: | See 1639.0 for VMS V5.3 kit; 2043.0 for 5.4 IFT kit |
| Moderator: | STAR::VATNE |
| Created: | Mon Oct 30 1989 |
| Last Modified: | Mon Dec 31 1990 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 3726 |
| Total number of notes: | 19516 |
A customer has pointed out to me that certain operations on
DECwindows widgets consume a lot of cpu resource even though on
the screen nothing is happening.
If you use a scroll bar widget and pick up the slider then the
cpu resource for a decterm application is about 6-8 % on a VS2000
when you do not move the mouse.When you do move the mouse then the
cpu usage goes up to about 25%.However if you select the arrow heads
or the non slider part of the scrollbar and press the mouse button
and hold it down the cpu usage is consistently 28-30%.When this
happens the server is not doing anything.In the situation where
the client and server are running on a single workstation this is
not too much of a problem.However where the client process is running
on a larger VAX with many other users then this might cause a
performmance problem if a number of users are inadvertently
holding down the mouse button in the wrong place. This is what is
worrying the customer.
Can anyone explain exactly what is happening and is there anything
that can be done to avoid it (other than user education or chopping
off the hands of fidgety employees).
regards Mark
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 807.1 | Would users really do this if it's a noop? | POOL::CAFARELLA | Fri May 19 1989 14:44 | 20 | |
Something is unclear about your customer's concern. If the user clicks and holds on the arrow or the non-slider portion of the bar, he must want to see something scroll. If nothing happens on the screen, then the application is not performing the desired scroll operation. This sounds like a flawed application (or maybe it's actually scrolling blank lines). I'm not sure what's happening internally in the toolkit during this kind of scroll. But, in any event, if nothing happens on the screen, it's unlikely that users will continue to do this operation, advertently or inadvertently. I can understand that it's disconcerting that CPU can be used up when nothing seems to be happening, but, in practice, I doubt that users will do this once they know it is not useful to them. Tom Cafarella, VMS Performance Group | |||||
| 807.2 | 38863::DERAMO | Daniel V. {AITG,ZFC}:: D'Eramo | Fri May 19 1989 21:02 | 10 | |
When you do that with a DECterm, you quickly scroll to the end and then it seems as if nothing is happening. But if you use a DECwindows Notes widget instead, you do see something happening: after quickly scrolling to the end, the mouse rapidly oscillates between the "wait cursor" and its normal shape. The DECterm could be in the same tight loop but without the cursor change to make it visible. Dan | |||||
| 807.3 | ...Thanks | 42721::BULLARD | Play it again,SAMS | Wed May 24 1989 11:39 | 16 |
re. 1
Unfortunately the customers experience is that users tend to do
this if they know that it causes problems.Sad but true.In this
instance the application involve a plant monitoring system and users
get bored and fidgety if they have to stare at a near static screen
all day and so are likely to spend a lot of time scrolling back
and forth their mimic diagrams.
re.2 yes the customer will have to bear in mind that he can do
something from within his callback to try and make it obvious that
nothing is happening.
regards Mark
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