Re: Introduce a New Metrics to measure Load average.

[Erik Mouw <erik@harddisk-recovery.com>]

On Wed, Jun 14, 2006 at 03:12:29PM +1000, sena seneviratne wrote:
> The  problem with the load metric of current Linux/Unix is that it measures 
> CPU load and Disk load without indicating the true nature of the load, 
> thereby creating some confusion among the readers. For example, if a CPU 
> bound task switches on to read a large chunk of disk data, then the load 
> average value would still continue to indicate this activity as a load, yet 
> the true CPU load during this period would have been zero.

Right, we've seen such things with busy servers.

> This situation 
> triggered us to make necessary additions to the kernel so that CPU load and 
> Disk load could be reported separately. Further the specialisation of load 
> helped our model to perform predictions when there is interference between 
> CPU and Disk IO loads.

OK.

> In the user mode, a new proc file called /proc/loadavgus would collect the 
> new data according to a new format which would look like the following,
> 
>                 CPU    Disk
> Root            0.7     0
> User1   0.9     1
> User2   0.9     0
> User3   1.03    1
> User4   0.93    0
> User5   1.0     0

The kernel doesn't know about user names, only uids. So the layout
should be something like:

		CPU	Disk
0		0.7	0
500		0.9	1
501		0.9	0

> What do you think about this change?

Why do you want to tell the load per user? Just the CPU and disk load
should be sufficient.


Erik

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