Fine-grained logging down to the layer draw level is available through the logging level Info:Detailed. The detailed logging is especially helpful when troubleshooting performance. In this topic, consider the scenario that you have a map service that's not drawing as fast as you'd like.
Before you go to the logs, it may be easier to catch the problem using the Analyze button on the Map Service Publishing Toolbar. This toolbar can quickly point out areas for improvement in your map document. The map service definition (MSD) files created with this toolbar also result in much faster map services. See Publishing a map service for steps on creating an MSD-based map service with the Map Service Publishing Toolbar.
When you need more detail about what's happening during a map draw, you can go to the log files and enable the new detailed logging. This is the workflow you'd follow:
The Help topic Map service log codes contains a table of the codes you'll see when analyzing the detailed logging. If you scroll down the topic, you'll also find an example of the codes returned from a simple ExportMapImage request like the one that happens when you zoom or pan the map.
When examining detailed logs, you'll often see the messages "Server Context Created" and "Server Context Released". The time between the creation of the server context and its release is the time that the request spends in the GIS Server tier. If you determine that performance is acceptable in the GIS Server tier but your application is still slow, it's possible that your Web server is the bottleneck or that your application is spending time waiting for available service instances so it can get a server context.