Re: [Lse-tech] Re: A common layer for Accounting packages

[Kaigai Kohei <kaigai@ak.jp.nec.com>]

Hello, everyone.

Andrew Morton wrote:
 > Jay Lan <jlan@sgi.com> wrote:
 >
 >>Since the need of Linux system accounting has gone beyond what BSD
 >>accounting provides, i think it is a good idea to create a thin layer
 >>of common code for various accounting packages, such as BSD accounting,
 >>CSA, ELSA, etc. The hook to do_exit() at exit.c was changed to invoke
 >>a routine in the common code which would then invoke those accounting
 >>packages that register to the acct_common to handle do_exit situation.
 >
 >
 > This all seems to be heading in the wrong direction.  Do we really want to
 > have lots of different system accounting packages all hooking into a
 > generic we-cant-decide-what-to-do-so-we-added-some-pointless-overhead
 > framework?
 >
 > Can't we get _one_ accounting system in there, get it right, avoid the
 > framework?

I think there are two issues about system accounting framework.

Issue: 1) How to define the appropriate unit for accounting ?
Current BSD-accountiong make a collection per process accounting information.
CSA make additionally a collection per process-aggregation accounting.

It is appropriate to make the fork-exit event handling framework for definition
of the process-aggregation, such as PAGG.

This system-accounting per process-aggregation is quite useful,
thought I tried the SGI's implementation named 'job' in past days.


Issue: 2) What items should be collected for accounting information ?
BSD-accounting collects PID/UID/GID, User/Sys/Elapsed-Time, and # of
minor/major page faults. SGI's CSA collects VM/RSS size on exit time,
Integral-VM/RSS, and amount of block-I/O additionally.

I think it's hard to implement the accounting-engine as a kernel loadable
module using any kinds of framework. Because, we must put callback functions
into all around the kernel for this purpose.

Thus, I make a proposion as follows:
We should separate the process-aggregation functionality and collecting
accounting informations.
Something of framework to implement process-aggregation is necessary.
And, making a collection of accounting information should be merged
into BSD-accounting and implemented as a part of monolithic kernel
as Guillaume said.

Thanks.
-- 
Linux Promotion Center, NEC
KaiGai Kohei <kaigai@ak.jp.nec.com>