On Fri, 18 Jan 2008 17:26:09 -0500
[EMAIL PROTECTED] (Frank Ch. Eigler) wrote:
> Arjan van de Ven <[EMAIL PROTECTED]> writes:
>
> > This patch contains the first set of instrumentations for
> > latencytop; each instrumentation needs to be evaluated for
> > usefulness before this can go into mainline; posting here just to
> > show how the infrastructure can be used
> > [...]
>
> Can you suggest of some reason why all this instrumentation could
> not be in the form of standard markers (perhaps conditionally
> compiled out if necessary)?
>
sure. Every instrumentation you see is of the nested kind (since the lowest
level
of nesting is already automatic via wchan).
If markers can provide me the following semantics, I'd be MORE than happy to
use markers:
If the code path is like this
set_latency_reason("Reading file");
....
....
set_latency_reason("Allocating memory");
kmalloc() <--- blocks for 100 msec
restore_latency_reason()
....
restore_latency_reason();
via several layers of functions, the requirement is that the 100 msec is
accounted
to "reading file" and not "Allocating memory". But if some other codepath hits
the allocating memory function,
without an outer "set_latency_reason", it should be accounted to "Allocating
memory".
If markers can provide that semantics ... you sold me.
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