Analyze Performance with Pipeline Profiler
Use the Pipeline Profiler to tune the performance of scripts and pipelines during development and testing. The Pipeline Profiler collects and aggregates pipeline run times for each node and script in a pipeline. You must trigger the pipeline in the storefront so that the Pipeline Profiler can analyze its performance. You can use this information to identify problem areas of code.
We recommend that you use the Pipeline Profiler during both development and load testing. The performance of a pipeline depends on the tasks it's intended to accomplish. As a general rule, a pipeline shouldn't take more than three seconds to execute when it includes non-cached components and no more than 250 milliseconds when it includes cached components. These guidelines assume that there might be additional performance costs to constructing a page in addition to the pipeline, for example, executing JavaScript or retrieving rich content, such as flash content. Generally, you can expect that performance load testing might also be required to judge the performance of a page on a live site. The Pipeline Profiler is a useful tool for examining pipelines during this phase of testing.
Refer also to Use Code Profiler for information about analyzing run-time performance.