GSoC Project | Basic Support for Trace Compass

[Ravindra Kumar Meena]

>
> >      >     Creating the metadata is one of the first actions a plugin
> >     must do
> >      >
> >      > Okay.
> >      >
> >      > I sent you one metadata file which had 1160 events. So should I
> >     add the
> >      > rtems 512 events in metadata?
> >
> >     At the moment a detailed description of individual events is not
> >     necessary. We have to get the basics in place first. So for now an 10
> >     bit event number is enough.
> >
> > in recorddata.h I can see that out of 32 bits 10 bits are reserved for
> > event and 22 bits are reserved for time of the event.
> > With event number you mean 10 bits reserved for events?
>
> Yes.
>
Okay.

>
> >
> >
> >      >
> >      > The problem I am facing here is how to relate the metadata file
> with
> >      > rtems event record item?
> >
> >     This depends on what you want to do. It seems the babeltrace plugin
> >     is a
> >     bit too complex to write at the moment. Maybe we should start with
> >     something simpler.
> >
> >     The record client in your rtems-tools repository does the following:
> >
> >     target --> TCP stream with struct rtems_record_items -> client ->
> >     conversion -> human readable text
> >
> > Okay
> >
> >
> >     We should turn this into:
> >
> >     target --> TCP stream with struct rtems_record_items -> client ->
> >     conversion ->
> >
> > Okay up to this everything is working fine .
> >
> >     CTF (metadata + event stream) -> files -> babeltrace ->
> >     human readable text
> >
> > We have to deal with this.
> >
> >
> >     So the first thing we have to figure out is how babeltrace reads an
> >     arbitrary CTF session (metadata + event stream).
> >
> >
> >     The next thing is to look at and modify print_item() in
> >     misc/record/record-main.c. In this function you get one client_item
> >     after another.
> >
> >     typedef struct client_item {
> >         union {
> >           SLIST_ENTRY( client_item ) free_node;
> >           RB_ENTRY( client_item )    active_node;
> >         };
> >         uint64_t                     ns;
> >         uint32_t                     cpu;
> >         rtems_record_event           event;
> >         uint64_t                     data;
> >         uint64_t                     counter;
> >     } client_item;
> >
> >     We are only interested in ns, cpu, event and data. So just convert
> >     this to
> >
> >     typedef struct {
> >         uint64_t                     ns;
> >         uint32_t                     cpu;
> >         rtems_record_event           event;
> >         uint64_t                     data;
> >     } ctf_event;
> >
> > If we are removing SLIST_ENTRY( client_item ) and RB_ENTRY( client_item
> > ) then we will also have to remove it's SLIST_HEAD(), RB_HEAD() etc.
>
> What do you mean with "remove it's SLIST_HEAD(), RB_HEAD() etc."?
>
Okay. I saw it wrong. I thought these are dependent on SLIST_ENTRY(
client_item ) and RB_ENTRY( client_item).

>
> In print_item() you get a client_item which contains also implementation
> details of the client (the nodes and the counter). These members are not
> relevant for the converted event stream.
>
Okay

>
> >
> >
> >     and append this item into a file (the event stream file). For this
> >     ctf_event you need a TSDL metadata. Save this metadata file.
> >
> > I have tried babeltrace example [1]. The babeltrace was using generated
> > metadata file.
> > We can also try barectf. It just needs yaml file which generated c code.
>
> Why do we need additional tools here? Is it not sufficient to generate
> the metadata in plain text format and save the event stream as binary data?
>
I was just trying barectf yesterday. I was able to generate metadata file
with it. YAML file is very easy to write.  I used "barectf config.yaml -m
ctf" command.

>
> >
> >
> >     Import the metadata and event stream in babeltrace and let it print a
> >     human readable form.
> >
> >     Does this look like something you can do?
> >
> > Okay. I will try. This was very much helpful but I think babeltrace will
> > definitely need generated metadata file.
> >
> > [1] https://lists.rtems.org/pipermail/devel/2019-May/025921.html
>
> The metadata is a part of CTF, so everyone consuming CTF data needs it.
>
Okay


-- 
*Ravindra Kumar Meena*,
B. Tech. Computer Science and Engineering,
Indian Institute of Technology (Indian School of Mines)
<https://www.iitism.ac.in/>, Dhanbad
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