Re: [patch 1/2] fork_connector: add a fork connector

[Jay Lan <jlan@engr.sgi.com>]

Paul Jackson wrote:
> Guillaume wrote:
>
> >  The goal of the fork connector is to inform a user space application
> > that a fork occurs in the kernel. This information (cpu ID, parent PID
> > and child PID) can be used by several user space applications. It's not
> > only for accounting. Accounting and fork_connector are two different
> > things and thus, fork_connector doesn't do the merge of any kinds of
> > data (and it will never do). 
>
>
> Yes - it is clear that the fork_connector does this - inform user space
> of fork information <cpu, parent, child>.  I'm not saying that
> fork_connector should merge data; I'm observing that it doesn't, and
> that this would seem to serve the needs of accounting poorly.

Paul,

You probably can look at it this way: the accounting data being
written out by BSD are per process data and the fork connector
provides information needed to group processes into process
aggregates.

Thanks,
 - jay

> Out of curiosity, what are these 'several user space applications?'  The
> only one I know of is this extension to bsd accounting to include
> capturing parent and child pid at fork.  Probably you've mentioned some
> other uses of fork_connector before here, but I missed it.
>
>
> > The relayfs is done, like Evgeniy said, for large amount of
> > datas. So I think that it's not suitable for what we want to achieve
> > with the fork connector.
>
>
> I never claimed that relayfs was appropriate for fork_connector.
>
> I'm not trying to tape a rock to Evgeniy's screwdriver.  I'm saying that
> accounting looks like a nail to me, so let us see what rocks and hammers
> we have in our tool box.

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