Re: [PATCH] perf record: Allow to disable callchains by setting mode to "none"

[Milian Wolff <milian.wolff@kdab.com>]

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Hey,

sorry for the noise. This patch can be dropped. Not only is it broken (doesn't 
set param->enabled = false), the functionality I was looking for exists 
already in the form of call-graph=no (see evsel.c).

Is there a reason that the disabling feature is handled outside of 
parse_callchain_record? Otherwise one should centralize the code imo for 
readability.

I'd also like to see "none" being accepted as a synonym to "no".

If any of the two things above sound valid, then I'd respin the patch below 
attend to them.

Cheers

On Dienstag, 16. August 2016 12:34:27 CEST Milian Wolff wrote:
> This change is mostly useful for symmetry purposes. Before, we could:
> 
>     --event foo/call-graph=fp/
>     --event bar/call-graph=dwarf/
>     --event asdf/call-graph=lbr/
> 
> Now, we can also use
> 
>     --event xyz/call-graph=none/
> 
> The latter is equivalent to
> 
>     --event xyz
> 
> when the `perf record` invocation does not specify a global call-graph
> option. If it does, then this patch also allows us to selectively
> disable the call-graph for single events.
> 
> Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
> ---
>  tools/perf/util/util.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
> index 85c5680..a549fee 100644
> --- a/tools/perf/util/util.c
> +++ b/tools/perf/util/util.c
> @@ -536,6 +536,14 @@ int parse_callchain_record(const char *arg, struct
> callchain_param *param) pr_err("callchain: No more arguments "
>  					"needed for --call-graph lbr\n");
>  			break;
> +		} else if (!strncmp(name, "none", sizeof("none"))) {
> +			if (!strtok_r(NULL, ",", &saveptr)) {
> +				param->record_mode = CALLCHAIN_NONE;
> +				ret = 0;
> +			} else
> +				pr_err("callchain: No more arguments "
> +					"needed for --call-graph none\n");
> +			break;
>  		} else {
>  			pr_err("callchain: Unknown --call-graph option "
>  			       "value: %s\n", arg);


-- 
Milian Wolff | milian.wolff@kdab.com | Software Engineer
KDAB (Deutschland) GmbH&Co KG, a KDAB Group company
Tel: +49-30-521325470
KDAB - The Qt Experts

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