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RE: [cdt-dev] Displaying DSF stack frames

Title: Displaying DSF stack frames
I just found that there seems to be a bug in the cache flushing logic:
 Bug 310992 - [vm][cache] Unnecessary cache flushing of thread children on suspended event
 
By fixing this, the stack depth retrieval can be avoided (until the full stack refresh happens).
 
Toni


From: cdt-dev-bounces@xxxxxxxxxxx [mailto:cdt-dev-bounces@xxxxxxxxxxx] On Behalf Of Pawel Piech
Sent: Wednesday, April 28, 2010 6:39 PM
To: CDT General developers list.
Subject: Re: [cdt-dev] Displaying DSF stack frames

Hi,
IStack.getTopFrame() and the delayed refresh logic in StackFramesVMNode is primarily intended at optimizing stepping speed.  When stepping, the full refresh of the stack frames is delayed by 200ms and if in that time a new step is executed, then the refresh is canceled.  However, this mechanism relies on the stack service for caching some stack information while the target is stepping stepping so it's not ideal.  Specifically, as you pointed out the stack depth is retrieved from the service to calculate the select delta for the top stack frame.  I think we could avoid this call if we were to enhance the view model cache a little bit.  I recently filed a bug for this: https://bugs.eclipse.org/bugs/show_bug.cgi?id=310518.

Cheers,
Pawel

On 04/28/2010 06:10 AM, ken.ryall@xxxxxxxxx wrote:
Pawel,

I’m working on optimizing bits of the EDC debugger and have run across an issue with displaying stack frames. In some circumstances when we’re building the list of stack frames determining the next frame can become an lengthy operation. This would be seem to be what IStack.getTopFrame is designed to do, just return the first one to give the user immediate feedback when a context is suspended, then bring in the remainder of the frames later. But IStack.getStackDepth is also called, which I understand is supposed to always return the complete number of frames, which will bring on some of the lengthy work I’m trying to defer.

So I must be misunderstanding how this works, I’m looking into it but I thought I would see if you had any advice.

Thanks - Ken
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