Re: [Qemu-devel] [PATCH 3/3] pseries: Add DPRINTF macros to spapr pci code

[Peter Maydell]

On 4 April 2012 20:18, Blue Swirl <address@hidden> wrote:
> On Mon, Apr 2, 2012 at 04:17, David Gibson <address@hidden> wrote:
>> From: Alexey Kardashevskiy <address@hidden>
>> This adds DPRINTF() macros with the usual conventions to the spapr_pci
>> code.
>
> Please use tracepoints instead of printf statements. Tracing is more
> flexible, more efficient and does not suffer from bitrot.

I'd much rather enable a #define to turn on debugging than faff about
with tracing. It's simple and straightforward, you can do it with a
single obvious change and recompile, and nobody has to look up
documentation to figure out how it works.

If tracepoints were always-compiled-in and enabled at runtime I'd
agree with you: then you could have linux-kernel-style "enable debug
tracing", "enable warnings about odd guest behaviour", "be silent",
etc. But they're not, so they don't gain anything over a simple
DPRINTF for programmer debugging.

-- PMM