Re: [PATCH dwarves] pahole: only warn about multithreading in verbose mode

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Thu, Aug 01, 2024 at 10:50:58AM +0100, Alan Maguire wrote:
> For kernel builds, pahole is called with -j to specify multithreading
> as long as it is >= 1.22.  However, if elfutils are older than 0.178
> at compile time, multithreading is not supported and we emit a
> warning to stderr.  The problem is this message will be emitted each
> time pahole is run, and this translates to thousands of times in a
> kernel build (once for vmlinux and once for each module).  Often users
> who are not familiar with BTF generation or pahole reasonably assume
> this is an error, whereas it is actually fine; it just means that
> pahole is a bit slower to generate BTF.
> 
> Move the message to verbose mode only, as in debugging cases it is
> important to know if pahole is running in parallel.

Thanks, applied to tmp.perf-tools-next,

- Arnaldo
 
> Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
> ---
>  pahole.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/pahole.c b/pahole.c
> index dd5002a..4db5107 100644
> --- a/pahole.c
> +++ b/pahole.c
> @@ -1889,7 +1889,8 @@ static error_t pahole__options_parser(int key, char *arg,
>  		  conf_load.nr_jobs = arg ? atoi(arg) :
>  					    sysconf(_SC_NPROCESSORS_ONLN) * 1.1;
>  #else
> -		  fputs("pahole: Multithreading requires elfutils >= 0.178. Continuing with a single thread...\n", stderr);
> +		  if (global_verbose)
> +			  fputs("pahole: Multithreading requires elfutils >= 0.178. Continuing with a single thread...\n", stderr);
>  #endif
>  							break;
>  	case ARGP_btf_encode_detached:
> -- 
> 2.43.5