I'm trying to find the actual GPU processor load on my iMac with the M290x. The load average being reported never goes above 5, even when running Cinebench 3d benchmarks. Certainly that doesn't mean only 5% GPU utilization does it?

How do I interpret the Load Average (i assume that it's the reading for the GPU)? I've attached a screen shot.

Running latest Yosemite.

  • Apparently latest version of iStat Menus shows processor usage for GPU as well. – Franklin Yu Jan 8 at 3:58

Load average is CPU based, not GPU based. The numbers represent one, five, and fifteen minute averages of the load on the CPU.

A single-core CPU is like a single lane of traffic. Imagine you are a bridge operator ... sometimes your bridge is so busy there are cars lined up to cross. You want to let folks know how traffic is moving on your bridge. A decent metric would be how many cars are waiting at a particular time. If no cars are waiting, incoming drivers know they can drive across right away. If cars are backed up, drivers know they're in for delays.

Source: http://blog.scoutapp.com/articles/2009/07/31/understanding-load-averages

1 core with a load of 1 means that core is 100% busy. But you can add loads when heaving more cores. 4 cpu's with a load of 1 means the total of the 4 cores is 25% busy, a load of 4 means 100%. A load higher than the number of cores means that the cores can not handle the load an the cpu is running 100% per core (and is the bottleneck of your system)

  • so, in theory, because that computer has 4 logical cores and hyperthreading, the max the Load Average can go to is 8? – v15 Jun 29 '15 at 17:28
  • @zm15 There is no 'maximum' load, but full utilisation would be 8.00, yes. – grg Jun 29 '15 at 17:29
  • So is there any way to monitor GPU usage in OS X? Perhaps through the terminal? – v15 Jun 29 '15 at 17:32
  • @zm15 If you have a NVIDIA card, you can use nvidia-smi – grg Jun 29 '15 at 17:35
  • @zm15. There is no analog to 'load' that I know of. You could look at the temperature and fan speed and use that. But I usually looked at my FPS, that was what mattered for me when I used to play. – CousinCocaine Jun 29 '15 at 17:36

Open up the terminal and type

man getloadaverage

To quote the man page:

The getloadavg() function returns the number of processes in the system run queue averaged over various periods of time. Up to nelem samples are retrieved and assigned to successive elements of loadavg[]. The system imposes a maximum of 3 samples, representing averages over the last 1, 5, and 15 minutes, respectively.

Note that, typically, for UNIX/Linux systems, a system with with no load should have these three numbers close to zero (lower bound). For Mac OS X Mavericks and later versions, this lower bound seems to be closer to 1, probably due to the way the system scheduler works.

  • My macOS doesn’t has this manual page. According to the quoted text, did you mean getloadavg(3)? – Franklin Yu Jan 5 at 23:04

"Hardware acceleration" could also contribute to load average (without bottlenecking).

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