This is the mail archive of the systemtap@sourceware.org mailing list for the systemtap project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [Ksummit-2008-discuss] DTrace


On Sat, Jul 05, 2008 at 12:05:36PM +0200, Christoph Hellwig wrote:
> On Sat, Jul 05, 2008 at 11:44:09AM +0200, Peter Zijlstra wrote:
> > Also, it would be really great if you could write probes in regular C,
> > some pseudo C language just messes up my mind.
> 
> You can write probes in plain C, in fact I do this all the time.  what's
> missing is a nice and easy to use channel to get the traces to userspace
> and interpret them, and helper for poking at kernel data structures.
>
As you might be aware the "trace" interface which is part of the -mm
tree was meant to satisfy such needs.

Moreover, an enhancement over the "trace" interface introduced in the form
of relay_printk() [for string output] and relay_dump() [for binary output]
was meant to give the user a printk()-like interface, but with the
advantages of using relay (such as per-cpu buffers) is still waiting for
acceptance and use-cases (Refer http://lkml.org/lkml/2008/5/28/212). A
typical example illustrating the brevity of the code when using the
relay_printk() interface can be found in the
samples/trace/fork_new_trace.c file in the patch.

Thanks,
K.Prasad
 


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]