btetto

A tool that produces Perfetto protobuf from formatted bpftrace output.

Usage

$ sudo bpftrace my_script.bt -f json | ./btetto.py
Attached probes: 4
^C
Writing 149 events to trace file: bpftrace_trace.binpb

btetto.py produces a bpftrace_trace.binpb protobuf file, which can then be loaded into the Perfetto UI.

bpftrace Output Format

The print output from bpftrace should be tuples (in JSON format e.g. -f json) where the first item in the tuple is the event type and the rest of the items are key value pairs e.g. ("track_event", "name", "page_fault_user", "type", "END")

Event Types

• track_event
• track_descriptor
• call_stack

Track Events (Spans)

These have three types: "BEGIN", "END", and "COUNTER" where "ts" is the timestamp of when these events occurred.

Required Fields:

• name
• ts
• type

Optional Fields:

• pid
• thread_name
• tid
• track_name

print(("track_event", "name", "page_fault_user", "type", "END", "ts", nsecs, "pid", pid, "tid", tid, "thread_name", comm));

Track Descriptor

These define track names in the Perfetto UI. At the moment only "track_event" event types can utilize custom tracks and to do that they need to set the track name in your track event e.g. (..., "track_name", "Sub Parent A").

There are three different types of descriptors:

• name
• thread_name
• counter

name

These are generic descriptors and can specify a "parent".

print(("track_descriptor", "name", "Top Parent"));
print(("track_descriptor", "name", "Sub Parent A", "parent", "Top Parent"));

thread_name

These are specifically for naming pid/tid tracks and require both the "pid" and "tid" pairs.

print(("track_descriptor", "thread_name", comm, "pid", pid, "tid", tid));

counter

These are for "COUNTER" type track events and require a "unit", which can be:

• unspecified
• count
• size_bytes
• time_ns

print(("track_descriptor", "counter", "Donut Counts", "unit", "count"));

Call Stack

These are for logging call stacks (kernel, user, or both) at specific points in time. They do not have durations.

Required Fields:

• pid
• tid
• ts
• kstack or ustack (or both)

Optional Fields:

• thread_name

print(("call_stack", "ts", nsecs, "pid", pid, "tid", tid, "thread_name", comm, "kstack", kstack, "ustack", ustack));