1# Overhauled performance tracing in Chrome 2 3We are upgrading Chrome's support for performance tracing by replacing Chrome's implementation of 4TRACE_EVENT macros from //base/trace_event with [Perfetto](https://perfetto.dev). Perfetto 5introduces [trace events with typed 6arguments](https://perfetto.dev/docs/instrumentation/track-events) to support privacy-filtered trace 7recording and a more compact, efficient, and stable trace encoding. 8 9The Perfetto library itself lives in 10[AOSP](https://android.googlesource.com/platform/external/perfetto/) and is rolled in 11[/third_party/chrome/](https://cs.chromium.org/chromium/src/third_party/perfetto/). Progress is 12tracked on https://crbug.com/1006541. 13 14The code in this directory connects Chrome to Perfetto's [tracing 15SDK](https://perfetto.dev/docs/instrumentation/tracing-sdk), which implements trace event macros on 16top of Perfetto's [tracing service](https://perfetto.dev/docs/concepts/service-model). This service 17can be run in-process (e.g. in unit tests), as a Chrome mojo service (see //services/tracing), or as 18a system service on Android. 19 20For more details, see [Perfetto's documentation](https://docs.perfetto.dev), [Typed trace events in 21Chrome](https://docs.google.com/document/d/1f7tt4cb-JcA5bQFR1oXk60ncJPpkL02_Hi_Bc6MfTQk/edit#), and 22[Typed trace events in 23//base](https://docs.google.com/document/d/1UQ4Ez7B-TeowijOUuMXuoWj1amZcQ7E2abt3s4jaAEY/edit#). 24 25Note: The integration with Perfetto's SDK is work-in-progress (https://crbug.com/1006541) behind 26the gn flag "use_perfetto_client_library". 27