Interesting, Michal. RLocker just forces selected DB to stay in the DbCache.
It makes sense.
However, I also observed a terrible slowdown and it was in a different
situation. It was in Resco Viewer and it happened twice.
In both cases it concerned thumbnail construction phase on a single quite
large folder. (All other folders were fast at the same time.)
First time it was on a T5 for just a few runs. The folder had 17000 images.
When I made a simple trace release, the problem disappeared and it never
returned, even for the original RescoViewer.prc.
2nd time it was on a T650 and the folder had some 500 images. The problem
persisted for a few weeks (disregarding program changes, resets, other
installed/removed databases etc.) and then it disappeared. Due to this time
frame I had enough time to formulate (and reject) all possible hypotheses.
At bare minimum (when I eliminated all side influences) it looked like this:
Imagine the thumbnail view of any viewer - the phase when no thumbnails
exist and placeholder bmp's are shown instead.
Drawing a placeholder bmp (TBmp resource) in a 6x4 grid with some small
overhead (that did not include any DB or file operations ) took more than 5
seconds instead of 0.1 sec or something like this.
Another interesting observation: After the real thumbnails were constructed,
the bitmap drawing was so slow that I could nearly see each bitmap growing.
Finally, when the thumbnails were hidden, everything was fast.
Thumbnails are stored in a RAM DB of limited size. When the DB is full,
records that were not accessed for the longest time are purged. My first
idea was that the DbCache gets into some loop, but I found a number of
counter-arguments.
I can't do any testing anymore, but I am still very interested in the
explanation. I could start speculating about threads running in background,
but it would be just that - speculations.
Placeholder bmp I mentioned above was all the time locked using
DmGetResource + MemHandleLock.
With best regards,
Jan Slodicka
Resco, Palm Division
----- Original Message -----
From: "Michal Seliga" <[EMAIL PROTECTED]>
Newsgroups: palm-dev-forum
To: "Palm Developer Forum" <[email protected]>
Sent: Tuesday, September 05, 2006 6:40 PM
Subject: Re: Treo 650 slowdown?
> i had similar problem on tx - application started to behave very slowly
(items
> to list which were read from database almost immediately in ordinary
situations
> were drawing visibly one by one). softreset didn't helped. also dbcache
cleanup
> didn't helped
>
> then i installed resco locker and locked application with it and it worked
in
> good speed...
>
> then i removed lock and application itself and it still works well and it
didn't
> slowed down since then (its 2 months since then of almost daily usage)
>
> so i have no idea what happened there...but it happened and this resco
locker
> seemed to help. try it maybe it will help in your case too
>
>
>
> Stefan Mohr wrote:
> > Hi guys,
> >
> >
> > We've received a few reports from users of our software that the
> > performance on their Treo 650s is intermittently becoming extremely
> > slow.
> > We're doing survey software where the user can tap between questions -
> > in some of these cases, going to a new question can take up to 3
> > seconds, whereas normally (and on all other Palm devices) it takes under
> > a second.
> >
> > We're dealing with between 10-150 databases, each with 1-200 records
> > each (and typically around 30 records per @ <100 bytes per record).
> >
> > Has anyone encountered any problems with the Treos slowing down
> > horribly? The customer reported that a soft reset didn't improve
> > performance at all, but the issue doesn't appear across all the Treos he
> > is using.
> > I'm a bit stumped - I've suggested he run the Treo OS updater from Palm,
> > but I'm not too sure what to tell him.
> >
> > Thanks for any thoughts,
> > Stefan
> >
>
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