1# Visualising large traces 2 3Browsers often limit the amount of memory a site can use. 4This can cause problems when visualising large traces. 5 6## How to visualise large traces using the Perfetto UI 7 8Perfetto UI has support for a mode where the processing of the trace 9is offloaded to a 'server' instance of `trace_processor` running natively on your local machine. 10This server process can take full advantage of the RAM of your machine as well as running at full native (rather than WASM) performance. 11 12``` 13curl -LO https://get.perfetto.dev/trace_processor 14chmod +x ./trace_processor 15trace_processor --httpd /path/to/trace.pftrace 16# Navigate to http://ui.perfetto.dev, it will prompt to use the HTTP+RPC interface 17``` 18 19## How big is too big? 20 21The exact memory limit can vary by browser, architecture, and OS however 2gb is typical. 22This limit is a limit on the total memory used at runtime, not on the binary size of the trace. 23The `trace_processor` (and hence the UI) representation of a trace at runtime is normally larger than the binary size of that trace. 24This is because the representation is optimized for query performance rather than size. 25The exact inflation factor varies depending on the trace format but can be 2-4x for uncompressed proto traces. 26 27 28