Enabling ExampleGenerator.CACHING in  significantly improved performance in ConsoleCheckCLDR. However, when SurveyTool is running, there's a problem with DataSection.getExampleBuilder:
That "new ExampleBuilder()" gets called repeatedly even when all the simulated fast-voters (see survey-driver) are in the same locale. The cache doesn't persist long since each request from the client causes the server to create a new DataSection, which creates a new ExampleBuilder, which creates two new ExampleGenerator objects (one for englishFile, one for cldrFile).
Ideally the whole DataSection object could be re-used for multiple http requests as much as possible. This ticket should investigate that and other possible ways of re-using ExampleBuilder objects.