GC GC CMS data collection time

We have included garbage collection logs for our application. I see a few lines where it prints the time of some CMS steps. Can someone explain or point me to a link that explains CMS logs, for example

9657.238: [CMS-concurrent-mark: 17.199 / 17.396 secs] [Times: user = 80.61 sys = 10.00, real = 17.40 secs ]