Re: Integration of the shared memory based transport in the SystemTap

[David Smith <dsmith@redhat.com>]

I wonder if you wouldn't take a look at the existing ring buffer code
in the transport. We had it working at one point, but then never quite
pushed it over the finish line. I'm sure it needs some updates for
kernel changes. The advantage here would be that we're using an
existing kernel interface instead of rolling our own. Plus, a good bit
of the work has been done to integrate it with systemtap already. Look
in runtime/transport/ring_buffer.c.

On Tue, Jul 11, 2017 at 1:59 AM, Arkady <arkady.miasnikov@gmail.com> wrote:
> Hi,
>
> I have an implementation of shared memory which is, hopefully, rather
> close to the production grade. The idea is that a probe allocates a
> small chunk from the FIFO, fills the chunk with the data, "commits"
> the chunk. The FIFO can be lockless if there is a FIFO per core.
>
> This is the API in the kernel space
> https://gist.github.com/larytet/4977626fd87817414c7a88dd63e7855d
>
> In the user space the shared memory provides write()/read()/mmap() interfaces.
>
> I am going to patch the SystemTap by adding the API into the C code.
>
> I wonder if there is a chance for making the shared memory a first
> class citizen in the STAP and what will it take to merge the API into
> the mainline.
>
> Thank you, Arkady.



-- 
David Smith
Principal Software Engineer
Red Hat