Re: Too many calls to new?
At 09:15 PM 6/24/2003, Richard Coutts wrote: I believe that the m515 only has 256K of dynamic memory available to the device. Your global memory and your stack space is included in that value, so 200K may very well be the limit. Ah. Just so I'm clear on this -- the database resides in storage space, but since I'm loading every value of the database into a graph, then I'm effectively creating a copy of the database in dynamic memory, which is very limited in size on some devices? Is dynamic memory faster than storage memory? For reading, dynamic and storage memory is equivalent. For writing, memory on the dynamic heap can be written much quicker, as you don't have to go through pointer validation and memory protection. -- Ben Combee [EMAIL PROTECTED] CodeWarrior for Palm OS technical lead Palm OS programming help @ www.palmoswerks.com -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
Too many calls to new?
I'm getting an exception from within new on ROMs for older handhelds, such as the m515, when the number of calls to new exceeds 5000 or so. It's happening when reading a database. My database represents a drawing that has entities, such as lines, circles, etc. When reading a database, I make a call to new for each entity in the database. So, if there are 5000 lines in the database, I make 5000 calls to new, one for each line, and put all of the lines in a graph for rendering. A database that works fine on a Zire 71 is throwing an exception on an m515. Running the database with POSE I'm finding the exception thrown from within a call to new after 5000 or so entities. The entities are only taking up 200Kb or so of memory, so there's plenty of memory left or the m515. Is it possible that I'm running into some other limitation? Thanks, Rich -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
Re: Too many calls to new?
le 25/06/03 3:12, Richard Coutts à [EMAIL PROTECTED] a écrit :
I'm getting an exception from within new on ROMs for older handhelds, such
as the m515, when the number of calls to new exceeds 5000 or so.
It's happening when reading a database. My database represents a drawing
that has entities, such as lines, circles, etc. When reading a database, I
make a call to new for each entity in the database. So, if there are 5000
lines in the database, I make 5000 calls to new, one for each line, and
put all of the lines in a graph for rendering.
A database that works fine on a Zire 71 is throwing an exception on an m515.
Running the database with POSE I'm finding the exception thrown from within
a call to new after 5000 or so entities.
The entities are only taking up 200Kb or so of memory, so there's plenty of
memory left or the m515. Is it possible that I'm running into some other
limitation?
Thanks,
Rich
Well the memory available for storage is not fully available for the
application heap. So you're probably running into this limit.
Since the most widely used device is the PalmV with only 2MB, you should
consider very carefully the way you allocate all this data.
Since the data is already in memory (the database IS in memory), maybe you
don't need to allocate a copy of your data. Certainly, your code looks like
the following:
switch(objkind)
{
case 'line':
obj = new lineobj(); // allocates data
break;
case 'circ':
obj = new circleobj();
break;
...
}
obj-InitFromRecord(); // copies data from database
obj-Draw();
You could write something like:
lineobj line;
circleobj circle;
switch(objkind)
{
case 'line':
obj = line; // no allocation (instance is in the stack)
break;
case 'circ':
obj = circle;
break;
...
}
obj-UseRecordData(); // refers to data in database (no copy)
obj-Draw();
Since you will avoid both an allocation and an initialization, this code
will probably run faster than your actual code, and will consume very little
memory.
---
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web: http://www.jlynx.com
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Re: Too many calls to new?
I believe that the m515 only has 256K of dynamic memory available to the device. Your global memory and your stack space is included in that value, so 200K may very well be the limit. Brad Richard Coutts [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] I'm getting an exception from within new on ROMs for older handhelds, such as the m515, when the number of calls to new exceeds 5000 or so. It's happening when reading a database. My database represents a drawing that has entities, such as lines, circles, etc. When reading a database, I make a call to new for each entity in the database. So, if there are 5000 lines in the database, I make 5000 calls to new, one for each line, and put all of the lines in a graph for rendering. A database that works fine on a Zire 71 is throwing an exception on an m515. Running the database with POSE I'm finding the exception thrown from within a call to new after 5000 or so entities. The entities are only taking up 200Kb or so of memory, so there's plenty of memory left or the m515. Is it possible that I'm running into some other limitation? Thanks, Rich -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
Re: Too many calls to new?
I believe that the m515 only has 256K of dynamic memory available to the device. Your global memory and your stack space is included in that value, so 200K may very well be the limit. Ah. Just so I'm clear on this -- the database resides in storage space, but since I'm loading every value of the database into a graph, then I'm effectively creating a copy of the database in dynamic memory, which is very limited in size on some devices? Is dynamic memory faster than storage memory? Thanks, Rich -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
RE: Too many calls to new?
Ah. Just so I'm clear on this -- the database resides in storage space, but since I'm loading every value of the database into a graph, then I'm effectively creating a copy of the database in dynamic memory, which is very limited in size on some devices? Correct. Take a look at some of the SDK samples like MemoPad to see how they manage to get by with hardly any dynamic heap allocations at all (I seem to recall that MemoPad allocates only one chunk out of the storage heap, which is used to hold the text of the variable form caption Memo xx of yy). Is dynamic memory faster than storage memory? It's not faster for reading, but it is faster for writing (since writing to the storage heap requires calls to DmWrite and friends). -- Keith -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
