Metadata: add env fields to ease life of viewer
Add the following field in the env section of the metadata:
- trace_name
The session name without datetime information.
Hence when the session is an auto-generated one, only print
LTTNG_DEFAULT_NAME.
- trace_creation_time:
The time at which the session was created.
We use session->creation time for it.
- tracer_buffering_scheme
The buffering scheme used. The value can be uid or pid.
- tracer_buffering_id
The key used by the buffering scheme (uid/pid).
- isa_length
The length of the ISA used. (e.g 32 or 64)
Addend these fields ensure that the trace itself carry information that
is normally carried via folder hierarchy. e.g
test-
20190417-174951/ <- trace_name
└── ust <- domain
└── uid <- tracer_buffering_scheme
└── 1000 <- tracer_buffering_id
└── 64-bit <- isa_length
├── channel0_0
├── channel0_1
├── channel0_2
├── channel0_3
├── index
│ ├── channel0_0.idx
│ ├── channel0_1.idx
│ ├── channel0_2.idx
│ └── channel0_3.idx
└── metadata
Per-pid buffering is quite similar.
Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>