| # Visualising large traces |
| |
| Browsers often limit the amount of memory a site can use. |
| This can cause problems when visualising large traces. |
| |
| ## How to visualise large traces using the Perfetto UI |
| |
| Perfetto UI has support for a mode where the processing of the trace |
| is offloaded to a 'server' instance of `trace_processor` running natively on your local machine. |
| This server process can take full advantage of the RAM of your machine as well as running at full native (rather than WASM) performance. |
| |
| ``` |
| curl -LO https://get.perfetto.dev/trace_processor |
| chmod +x ./trace_processor |
| trace_processor --httpd /path/to/trace.pftrace |
| # Navigate to http://ui.perfetto.dev, it will prompt to use the HTTP+RPC interface |
| ``` |
| |
| ## How big is too big? |
| |
| The exact memory limit can vary by browser, architecture, and OS however 2gb is typical. |
| This limit is a limit on the total memory used at runtime, not on the binary size of the trace. |
| The `trace_processor` (and hence the UI) representation of a trace at runtime is normally larger than the binary size of that trace. |
| This is because the representation is optimized for query performance rather than size. |
| The exact inflation factor varies depending on the trace format but can be 2-4x for uncompressed proto traces. |
| |
| |
