notes ui call 20070214

[Elena Zannoni <elena dot zannoni at oracle dot com>]

In case these are helpful, here are my notes for today's call.

Attendees:
RH: Andrew, Phil, Rich, Chris, Sami, Nurdin, Mike, Tim, Mark, Jonathan
Oracle: Kris, Elena


HPDF interface, with fhpd. -- Tim and Stan

Demonstrated command set with attach, go, halt, where, help, list

Tim: stop the world or stop individual threads? Right now it's stop the 
world.
But underlying mechanism to do stop each thread is there.

Tab completion: demoed

go is different from continue in hpdf. continue is blocking the hpd
interface, go doesn't. I.e. go is async, continue is sync.

breakpoints: can set breakpoints, and run (there is a bug, though that
Tim has a fix for, not checked in yet). Break syntax right now is
break <filename> <linenumber> needs refining.

print command can display arrays, array elements and classes

Can also print in different formats. print <var> -format [x|o]

Help <command> is totally broken


Can do "what <var name>" displays the type of the variable or function

disassembler: not hooked up to the hpd yet. Works in the source
window. Not demoed.

display of registers: there needs to be a refactoring. Not demoed.

volatile attribute can make a variable stick around even with optimization.

how about logging, should that be an option on start up of fhpd.

compatibility with gdb command set. it's needed, maybe a set of aliases.



Custom observers -- Sami

cagney: use "catch" instead of "Print" in the actions. To avoid
printing the whole backtrace for instance, since it can be too
long. Just show that the event has happened and stop there.

Fork observer has 2 callback functions: in one the parent is paused,
in the other the child is paused.  Picking an action on either thread,
the thread will be invoking the proper callback.

Some actions take arguments, like "add observer". Enter args in the
box to the right of the action selection box. There is an
autocompletion feature that is now broken, on the args.

no way to tell if all filters are valid or not for a given action if
filters and actions have been applied.

plus/minus buttons are confusing. Minus on the first one: what does it
do? unclear.

Is order of actions important?

How common is it to create custom observers? Frysk developers use them.

Custom written events are needed. Written using code.

Filters should be a short list

Interactions between actions and the radio buttons at the
bottom. Users could construct contradictory events/actions.

Open issue: How to best bind events to threads. One event can apply to
many threads


Conference call issues:

1. Wednesday 9:30AM seems to be better than Thursday 9:30AM. All agree
  to move call to Wed.

2. Request to open up the RH only conf call to all. For general status
  of the project, who works on what, progress reports, and
  dependencies/issue with other components (kernel, gcc, libunwind,
  etc) RH has things that cannot be discussed openly, will need to
  figure out how to avoid having 3 meetings. Elena's suggestion is to
  use the Wed call, and shorten the GUI part.