A customer was monitoring the CPU usage of one of their processes in the Performance Monitor tool, and they got a pretty graph and this summary: <\/p>\n
Average: 271,828<\/span> Minimum: 0,000<\/span> Maximum: 3.141,592<\/span> <\/td>\n<\/tr>\n| Scale<\/td>\n | Counter<\/td>\n | Instance<\/td>\n | Parent<\/td>\n | Object<\/td>\n | Computer<\/td>\n<\/tr>\n | 0,1<\/td>\n | % Processor Time<\/td>\n | myapp<\/td>\n | —<\/td>\n | Process<\/td>\n | \\\\MYPC<\/td>\n<\/tr>\n<\/table>\n | What did the process consume 271828 of? What does this number mean in the context of percent processor time? <\/p>\n FIrst thing to notice is that the comma is a decimal separator, not a thousands separator. You see a clue there in the Scale<\/i> column, where it says “0,1”. Also in the Maximum<\/i>, where it says “3.141,592”, where the period after the “3” makes no sense if the comma were a decimal separator. Nope, this information is displayed according to a locale where the comma is the decimal separator and the period is the thousands separator. <\/p>\n Okay, so that unwraps one layer of the onion. We were misreading the value. It’s actually 271.828. But 271.828 what? <\/p>\n The next clue is that Scale<\/i>. It is set to 0.1, which means that the displayed value is tenths of a unit. So you didn’t consume 271.828 units, but rather 271.828 tenths of a unit, or 27.1828 units. <\/p>\n The next clue is that the value itself is called % Processor Time<\/i>, which tells you that that it is reporting in percentage of processor time. <\/p>\n Therefore, this process consumed 27% of a processor on average during the period under measurement. The maximum was 3141.592 × 0.1 = 314.1592 percent of a processor. In other words, during its peak, the process used the equivalent of 3.14 processors. (One can infer, then, that this system has at least four processors.) <\/p>\n To get to the final answer, we had to go through three layers: <\/p>\n |