*** note This doc is WIP, stay tuned.
This doc should show the charts of perfetto_benchmarks, showing cpu usage and
tracing bandwidth for both writing (producer->service) and reading
(service->file / service->consumer).
In two modes:
- Measure peak tracing bandwidth saturating the cpu: the producer(s) write as much data as they can, reaching 100% cpu usage.
- Measure CPU overhead vs constant bandwidth: the producer(s) writes data at a pre-defined rate.
Tweaking the various parameters, such as:
- Number of writers
- Size of the shared memory buffer
- Size of each TracePacket.
TL;DR:
Peak producer-to-service tracing bandwidth:
- Linux desktop: ~1.3 GB/s
- Android Pixel: ~1 GB/s
Producer-to-service CPU overhead when writing ~3 MB/s: 0.01 - 0.03 (0.01 := 1% cpu time of one core)
CPU overhead for translating ftrace raw pipe into protobuf:
- Android Pixel: 0.00-0.01 when idle.
- Android Pixel: 0.02-0.04 with 8 cores @ 8.0 CPU usage (raytracer).
- Linux desktop: TBD