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

From: Jay Lan
Date: Tue Mar 29 2005 - 13:45:36 EST


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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