What does vmlinux module do?

[gauthamt]

I wrote a simple routine that basically traverses a huge array list and touching only one entry per cache block. I basically wanted to stress the L1-Cache. I used remote sampling to evaluate this application on a Linux box.

My module view for different sampled processes (including my application) shows a lot of vmlinux with large memory misses. Does anyone know what this kernel module does?. I want to clarify whether it is connected in anyway to the remote sampling process (because I get it even when I sample the remote machine without any user processes running on it).

Thanks

[Daniel_B_Intel2]

the default view after sampling collection is the modules view for ALL processes.
If you want to see module view only for your process, first click process view, then choose your process, and only then click on module view.

does it help?
-Daniel

[gauthamt]

I understand. But I wanted to know what the vmlinux module does (since it seems to encounter so many misses).

I wanted to know whether it is related to the remote agent module execution on the linux box.

[Daniel_B_Intel2]

hi,

well there is also non-remote version (native) of VTune on Linux, with command line interface.
Have you tried it? (see more info on this tool in VTune for Linux forum, next to this one)

unfortunately i have no precise answer to your question.

in tuning methodology VTune serves for the reasonable numbers are not actually the number of events (like cache misses) but rater the ratios (please see more info on different ratios in VTune help)

as an interesting experiment you can conduct is to build kernel not stripped and run sampling collection again. then you will probably get the function names along with hotspots. this info migh answer better to your question?

-Daniel

[juffa]

The vmlinux module is the Linux kernel. I am just guessing but your test may create a lot paging activity in addition to stressing the L1 cache.

-- Norbert

[bnshah]

Juffa you are correct the vmlinux module is the kernel. If you want to be able to drill down into the kernel, rebuild it w/ the -g option so it has symbols.