When the combined CPU time counter (jiffies) for all task in a process (i.e., /proc/<pid>/stat) exceeds approximately 2^32*100/1000 (ms to jiffies), it jumps to a large value nearing 2^64*100/100000000000 (ns to jiffies).<br />
<br />
This results in process stats freezing (i.e., the process appears to no longer be consuming CPU) and invalid runtimes to be reported by ps, top, and such.<br />
<br />
The CPU time counters for the individual tasks (jiffies) in the process (i.e., /proc/<pid>/tasks/<tid>) continue to increment as expected however. This is reflected in ps, top, and such showing actually usage in thread mode.
↧