Accounting changes

[Garance A Drosehn]

At 8:10 PM +1000 5/6/07, Peter Jeremy wrote:
>  > Garance A Drosehn wrote:
>
>>>I also wonder about using a time_t for ac_btime (starting time).
>>>Now that we're running freebsd on very fast, multi-processor systems,
>>>we might care whether "<this>-command" executed before "<that>-command",
>>>and we might wish to have better resolution for the start-time of a
>>>given command.
>
>On a multi-processor machine, both commands may have begun at the
>same time (measured to whatever precision you want).

Hmm.  Well, that is a good point...

>There are
>occasional discussions regarding file timestamps (lack of precision
>can confuse make) - which is a related issue.  The decision as to
>whether make ac_time a time_t or (eg) struct timespec is not obvious:
>There is a definite space disadvantage to increasing ac_time precision
>(though there's only one instance per accounting record so the problem
>isn't as serious as comp_t).  OTOH, I can see theoretical reasons for
>wanting to know which command came first.
>
>This is probably a question that needs wider discussion:  Has there
>been any request for greater precision within the FreeBSD user
>community?

Not that I know of, but it might be that everyone is so used to the
current resolution that they don't think much about changing it.

Recently I have had a few cases where I was debugging something, and
I did need time-resolution better than the nearest second.  Admittedly
those cases had nothing to do with these accounting records.  However,
I have had three separate cases where I've needed this in the past six
months or so, and I don't think I've ever needed sub-second resolution
before that.  I don't know that we need better resolution for this
version of the accounting-record format, but I suspect we will want it
at some point in the future.

-- 
Garance Alistair Drosehn     =               drosehn at rpi.edu
Senior Systems Programmer               or   gad at FreeBSD.org
Rensselaer Polytechnic Institute;             Troy, NY;  USA