| Primiano Tucci | b808373 | 2018-04-09 15:38:37 +0100 | [diff] [blame] | 1 | # Multi layer tracing |
| 2 | |
| 3 | *** note |
| 4 | **This doc is WIP**, stay tuned. |
| 5 | <!-- TODO(primiano): write multi-layer tracing doc. --> |
| 6 | *** |
| 7 | |
| 8 | This doc should explain how is possible to compose a hierarchy of tracing |
| 9 | services. The concrete use case is combining multiprocess tracing in Chromium |
| 10 | with Android's tracing daemons (think to hypervisors' nested page tables). |
| 11 | |
| 12 | The TL;DR of the trick is: |
| 13 | - ABI stability of the |
| 14 | [shared_memory_abi.h](/include/perfetto/tracing/core/shared_memory_abi.h) |
| 15 | - ABI stability of the IPC surface. |
| 16 | |
| 17 | The tracing service in chromium should proxy Producer connections (adapting Mojo |
| 18 | to our IPC) towards the Android's `traced` service, passing back the shared |
| 19 | memory buffers to the real producers (the Chrome child process). |
| 20 | |
| 21 | Conceptually it is simple and straightforward, requires *some* care to implement |
| 22 | correctly ownership of the shared memory buffers though. |
