fuchsia_tracing

Namespaces

```
namespace wire
```

Enumerations

enum class BufferDisposition : uint8_t

Name	Value	Comments
kClearEntire	1u	Clear the entire buffer, including durable buffer contents. N.B. If this is done mid-session, then string and thread references from prior to this point will become invalid - the underlying data will be gone. To prevent this save buffer contents before clearing. This is typically used when buffer contents were saved after the preceding Stop.
kClearNondurable	2u	Clear the non-durable portion of the buffer, retaining the durable portion. This is typically used when buffer contents were not saved after the preceding Stop and the current contents are to be discarded.
kRetain	3u	Retain buffer contents. New trace data is added where the previous trace run left off. This is typically used when buffer contents were not saved after the preceding Stop and the current contents are to be retained.

Name

Value

Comments

kClearEntire

Clear the entire buffer, including durable buffer contents.
N.B. If this is done mid-session, then string and thread references
from prior to this point will become invalid - the underlying data
will be gone. To prevent this save buffer contents before clearing.

This is typically used when buffer contents were saved after the
preceding Stop.

kClearNondurable

Clear the non-durable portion of the buffer, retaining the durable
portion.

This is typically used when buffer contents were not saved after the
preceding Stop and the current contents are to be discarded.

kRetain

Retain buffer contents. New trace data is added where the previous
trace run left off.

This is typically used when buffer contents were not saved after the
preceding Stop and the current contents are to be retained.

Choices for clearing/retaining trace buffer contents at Start.

A brief summary of buffer contents:

The trace buffer is divided into two main pieces: durable and non-durable.

The durable portion contains things like the string and thread data for

their respective references (trace_encoded_string_ref_t and

trace_encoded_thread_ref_t). The non-durable portion contains the rest of

the trace data like events); this is the portion that, for example, is

discarded in circular buffering mode when the (non-durable) buffer fills.

Defined at line 25 of file fidling/gen/sdk/fidl/fuchsia.tracing/fuchsia.tracing/cpp/fidl/fuchsia.tracing/cpp/common_types.h

enum class BufferingMode : uint8_t

Name	Value	Comments
kOneshot	1u	In oneshot mode there is only one buffer that is not reused. When the buffer fills the provider just keeps dropping records, keeping a count, and then when tracing stops the header is updated to record final state.
kCircular	2u	In circular mode, the buffer is continually written to until tracing stops. When the buffer fills older records are discarded as needed.
kStreaming	3u	In streaming mode, the buffer is effectively split into two pieces. When one half of the buffer fills the provider notifies the trace manager via the provided fifo, and then starts filling the other half of the buffer. When the buffer is saved, the manager responds via the provided fifo. If trace manager hasn't saved the buffer in time, and the other buffer fills, then the provider is required to drop records until space becomes available.

The trace buffering mode.

Defined at line 62 of file fidling/gen/sdk/fidl/fuchsia.tracing/fuchsia.tracing/cpp/fidl/fuchsia.tracing/cpp/common_types.h

Records

```
class KnownCategory
```