Callgrind is a profiling tool and KCachegrind is able to visualize output of the profilers.
Profiling Viewer Alternatives
SaaSHub's Down Detector checks the status of services automatically and regularly. However, we cannot promise 100% accuracy. That is why we depend on user reported issues as well. The Profiling Viewer status here can help you determine if there is a global outage and Profiling Viewer is down for everyone or it is just you that is experiencing problems. Please always report any issues to help others know the current status.