Re: Integrate delay accounting with systemtap?

["Frank Ch. Eigler" <fche at redhat dot com>]

Hi -

On Thu, Jul 12, 2007 at 07:59:23PM +0530, Ananth N Mavinakayanahalli wrote:

> > [...]  But systemtap scripts already run in kernel space.  How/why
> > would you want them to talk across netlink sockets?

> See Documentation/accounting/getdelays.c

Yes, I see that, but this is exactly a user-space program using the
netlink api to query the kernel.  This scenario does not apply to
systemtap probes that run in kernel space.

> Given the data is available without any additional kernel
> probe/hook, it would be good for SystemTap to do something similar
> to getdelays.c

But the netlink widget is necessary primarly because user space has no
access to the task struct with all the statistics fields in it.  A
probe running in kernel space can access the task struct (more or
less) directly.

- FChE

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