I love atop - and install it everywhere that I can. The in depth metrics + historical view is excellent.<p>That being said, I wouldn't call it a one stop tool for performance analysis. Particularly due to the word 'analysis' - it tells you what resource was used, and what was using it. It doesn't tell you anything about /why/ the process was using it. It doesn't help with hunting down regressions. It doesn't give you insight in to what these processes are actually doing.<p>For that, you need to utilize strace/ltrace/ftrace/dtrace/ktap/systemtap/perf/sysdig/whatever<p>(If interested in the actual analysis/engineering side of performance, I recommend following Bredan Gregg's blog and buying his systems performance book - <a href="http://brendangregg.com/" rel="nofollow">http://brendangregg.com/</a> )
Atop was absolutely my favorite tool when I was supporting lots of interactive systems and users complained to me that "foo is slow". Even better, the logging let me determine the cause after the fact when a user complained "foo was slow". The beauty of it is that it's using process accounting to gather the resource utilization of everything that was running on the system between two points in time. Compare that to a more standard metrics-gathering system like collectd, where I would have to know the names of the processes I want to monitor in advance (<a href="http://collectd.org/documentation/manpages/collectd.conf.5.shtml#plugin_processes" rel="nofollow">http://collectd.org/documentation/manpages/collectd.conf.5.s...</a>).<p>The case study at <a href="http://www.atoptool.nl/download/case_leakage.pdf" rel="nofollow">http://www.atoptool.nl/download/case_leakage.pdf</a> is worth a read to get a feel for what it's like to use atop.