Re: [PATCH] libtracefs: An API to set the filtering of functions

[Sameeruddin Shaik <sameeruddin.shaik8@gmail.com>]

sure tzvetomir.

On Thu, Mar 4, 2021 at 2:29 PM Tzvetomir Stoyanov <tz.stoyanov@gmail.com> wrote:
>
> On Thu, Mar 4, 2021 at 9:24 AM Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > On Wed, 3 Mar 2021 06:46:26 +0530
> > Sameeruddin Shaik <sameeruddin.shaik8@gmail.com> wrote:
> >
> > > what if we store the indices of the failed filters in an integer array
> > > and return them back?
> >
> > There's not much difference if we return an array of pointers to the
> > filters or an array of integers to the index. I was just thinking about
> > how I would use the interface. When having a working interface, we
> > should write a few robust programs to see how easy it is to use, and
> > that will help in making the API appropriate. This needs to be done
> > *before* we accept it. This particular API is going to be widely used,
> > and it needs to be simple and robust.
>
> One remark, not directly related to this discussion. When the implementation
> of the API is ready, there should be a unit test (in a separate patch) - as for
> any of the other APIs. Usually these are the first use cases that I write for
> the new APIs.
> Sameer, please look at utest directory where the unit tests are, each API has
> a unit test there. We use the cunit framework, ask if there are questions about
> it. This should be the next step, when the final version of the
> implementation is
> ready.
> Thanks!
>
> >
> > > let's return the number of bytes written, also we will calculate the
> > > complete filters length and return it, if there is difference,
> > > we will loop into the integer array and print the erroneous filters
> >
> > Not sure how that is helpful. How would you use the number of bytes
> > written?
> >
> > >
> > > Let's fix the number of parameters to this function:)
> >
> > Not sure what you mean by that.
> >
> >
> > Here's how I envision this interface.
> >
> >         char **errs;
> >         char *filters[] = {
> >                 "sched*", "spin_*", NULL
> >         };
> >         int ret;
> >
> >
> >         ret = tracefs_function_filter(NULL, filters, NULL, &errs);
> >         if (ret < 0) {
> >                 int i;
> >
> >                 printf("Failed to apply: ");
> >                 for (i = 0; errs[i]; i++) {
> >                         if (i)
> >                                 printf(", ");
> >                         printf("'%s'", errs[i]);
> >                 }
> >                 printf("\n";
> >                 exit(ret);
> >         }
> >
> > -- Steve
>
>
>
> --
> Tzvetomir (Ceco) Stoyanov
> VMware Open Source Technology Center