"The aim of these four patches is to introduce Virtual Machine time accounting," began Laurent Vivier. He described the first two patches as:
"1) As recent CPUs introduce a third running state, after 'user' and 'system', we need a new field, 'guest', in cpustat to store the time used by the CPU to run virtual CPU. Modify /proc/stat to display this new field.
"2) Like for cpustat, introduce the 'gtime' (guest time of the task) and 'cgtime' (guest time of the task children) fields for the tasks. Modify signal_struct and task_struct. Modify /proc/<pid>/stat to display these new fields."
Both Ingo Molnar and Rik van Riel responded favorably to the patch. Ingo replied, "the concept certainly looks sane to me," adding, "I'd suggest inclusion into 2.6.24." Regarding concerns that the new information at the end of the line could break utilities such as
ps, Rik assured that it would not, "we have added numbers to the cpu lines in /proc/stat since early 2.6. All the programs parsing /proc/stat should just scan for a number of numbers from the start of the line, without trying to scan for the terminating newline."