atop

[Clint Byrum]

On Jun 30, 2010, at 1:10 PM, Tim Gardner wrote:
> 
> You are correct in that I am reluctant to drag in unmaintained crack 
> into core kernel structures.
> 
> I still find 'better task accounting' to be insufficient justification. 
> What specifically makes for better task accounting? Why is atop better 
> then other methods? As far as I can tell the current patches still 
> suffer from the deficiencies mentioned by Andrew Morton in
> http://marc.info/?l=linux-kernel&m=120716470803492&w=2
> 
> Gimme an example of a problem that atop will help solve for which no 
> other method will suffice.
> 

I just recently was contacted by a friend looking for help on periodic "total site freeze" issues with a web application. Atop revealed some badly behaving processes where regular top did not, because processes "in disk wait" might be waiting to read/write, and with hundreds of httpd's on the machine in disk wait, its painful to try and find out whats going on. Its such an instant revelation of activity, I really think as systems scale up these sorts of tools are really vital.

Whether atop as it is now is the way to do this remains to be decided. I recall talking with Cole Crawford at UDS about KSLM which may add similar capabilities to the kernel but in a more elegant way. I've CC'd Cole to get his opinion on this as well.