Re: [PATCH] new CSA patchset for 2.6.8

From: Jay Lan
Date: Thu Aug 26 2004 - 18:33:23 EST


I do like to see a common data collection method in the kernl. Kernel
does not need to decide how the data to be presented to the
user space. An accounting loadable module such as CSA or ELSA will
take care of how the data to be presented to meet the needs of
different users.

Sounds reasonable?

Regards,
- jay


Tim Schmielau wrote:
On Thu, 26 Aug 2004, Arthur Corliss wrote:


I would be very interested in a CSA implementation similar to what I have on
IRIX. I will also plead guilty to not having downloaded the updated patches
for either the kernel or the tools. I'm continuing to use my poor hack until
a permanent solution gets accepted into the kernel, at which point I'll
adopt that.


That's ok, we carefully discussed the changes to make sure no new tools
are required ;-)


And if it counters the impression at all, I'm not a kernel developer, I
proposed my hack out of need as a user of the tools. I also try to stay away
from modified kernels, so I'm running Marcelos' 2.4 stable branch with only
the 32bit u/gid_t hack applied. That's why I haven't had any feedback on the
-mm branch.


I haven't even tried to get a patch into 2.4, since Marcelo is (rightly)
quite resilent to new features.

In short, for my use BSD accounting is sufficient, but I'd love to see CSA in
Linux as well. Linux hasn't moved too far into roles where it's a necessity
(for what I'm doing, anyway), but I see CSA as something that would certainly
help it assume those roles.


Does this mean you would want to have both in the same kernel, potentially
turning on both at the same time?


Ok, let me summarize what I learned until now:

It should be easy to combine the data collection enhancements from
CSA and ELSA to provide a common superset of information.

Output file formats vary, but might be unified if projects don't insist
too much.
Main difference between CSA and ELSA on the one hand and BSD acct on the
other is that the latter writes one record per process, while the former
write one per job.
With the new BSD acct v3 format, it should be possible to do per job
accounting entirely from userspace, using pid and ppid information to
reconstruct the process tree and some userland database for the
pid -> job mapping. It would, however, be greatly simplified if the
accounting records provided some kind of job id, and some indicator
whether or not this process was the last of a job (group).

CSA and ELSA might even be more lightweight since fewer accounting records
are actually written.

Sounds like it should be possible to fulfill the different needs by
having loadable modules for the different output formats, or by a /proc
entry that controls some aspects like whether records are written per
job or per process.

Comments?

-
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