Re: [PATCH 1/1] rasd: Use perf_evlist__open() instead of open coded

David Ahern
2014-10-14T14:19:56Z

On 10/14/14, 7:56 AM, Jiri Olsa wrote:
> I read the rasd sources and realized we could poke this
> from another angle.. AFAIU the work the rasd does is following:
> - reads config file and opens configured tracepoints
> - reads samples comming from those tracepoints and displays/writes
> this data to the console/file
> - is there more?
>
> If I'm not missing anything, this is quite usefull/common usage
> pattern which would deserve new perf command.
>
> I can see the analogy with ftrace debugfs interface
> - choose/enable tracepoints
> - cat .../tracing/trace-pipe
>
> and there could be '-d' for the command to act as daemon.

Yes, this parallels a new use case on my end. Right now I am running
perf record ... | perf script. With the tracepoints and filters involved
it is a LOT of typing - and still collects more than is needed (I don't
need MMAP events for example, only COMM events). I am leaning towards a
new perf sub-command but from my scheduling timehist and daemon commands
I know there is a lot of overhead that goes with that. A perf library
with a stable API would make this a lot easier. (AFAIK the python
bindings do not currently support opening events, it is mainly an
analysis option.)

David