Re: [PATCH 05/16] tracing: show that buffer size is not expanded

KOSAKI Motohiro
2009-03-13T03:28:47Z

> > > # cat /debug/tracing/buffer_size_kb
> > > 7 (expanded: 1408)
> >
> > Hi,
> >
> > I have one question.
> > Why souldn't use following output?
> >
> > sprintf(buf, "%lu\n", trace_buf_size >> 10);
> >
> >
> > My point is:
> > - pure number output can hadle easily.
> > - nobody need to know internal memory saving logic.
>
> My answer to the second point is: "I do" ;-)
>
> I like to know the real buffer size. That '7' comes from the ring buffer
> size directly. If something is going wrong, I do not want to hide the fact
> that the ring buffer size is not what I expect it to be. Lets say someone
> modifies the code, and we miss expanding the buffer. It will be very hard
> to debug why we are getting a small trace. But if we see that the buffer
> has not been expanded, we know exactly what is wrong.

ok. understanding.
please ignore my last mail.

Thanks!