If I have a CPU with 8 cores, is it okay to have a consistent average load of 2.5? Or should it always remain below 1, irrespective of the number of processors / cores?
2 Answers
Let me cite from my training's documentation. This will answer your question.
The load average is displayed using three different sets of numbers, as shown in the following example:
The last piece of information is the average load of the system. Assuming our system is a single-CPU system, the 0.25 means that for the past minute, on average, the system has been 25% utilized. 0.12 in the next position means that over the past 5 minutes, on average, the system has been 12% utilized; and 0.15 in the final position means that over the past 15 minutes, on average, the system has been 15% utilized. If we saw a value of 1.00 in the second position, that would imply that the single-CPU system was 100% utilized, on average, over the past 5 minutes; this is good if we want to fully use a system. A value over 1.00 for a single-CPU system implies that the system was over-utilized: there were more processes needing CPU than CPU was available.
If we had more than one CPU, say a quad-CPU system, we would divide the load average numbers by the number of CPUs. In this case, for example, seeing a 1 minute load average of 4.00 implies that the system as a whole was 100% (4.00/4) utilized during the last minute.
Short term increases are usually not a problem. A high peak you see is likely a burst of activity, not a new level. For example, at start up, many processes start and then activity settles down. If a high peak is seen in the 5 and 15 minute load averages, it would may be cause for concern.
Yes. There is no specific load average that is okay or not okay, and because the load average measures I/O as well as CPU usage, the number of cores is basically irrelevant. If the system is performing acceptably, then it's acceptable. If not, not.
answered Mar 16, 2014 at 9:47
uptime.