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Date:   Wed, 12 Aug 2020 09:15:04 -0300
From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     Jin Yao <yao.jin@linux.intel.com>
Cc:     jolsa@kernel.org, peterz@infradead.org, mingo@redhat.com,
        alexander.shishkin@linux.intel.com, Linux-kernel@vger.kernel.org,
        ak@linux.intel.com, kan.liang@intel.com, yao.jin@intel.com,
        like.xu@linux.intel.com
Subject: Re: [PATCH] perf parse-events: Set exclude_guest for user-space
 counting
Message-ID: <20200812121504.GE13995@kernel.org>
References: <20200812065953.22143-1-yao.jin@linux.intel.com>
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Em Wed, Aug 12, 2020 at 02:59:53PM +0800, Jin Yao escreveu:
> Currently if we run 'perf record -e cycles:u', exclude_guest is 0.
> 
> But it doesn't make sense that we request for user-space counting
> but we also get the guest report.
> 
> To keep perf semantics consistent and clear, this patch sets
> exclude_guest for user-space counting.

Applied, and also added this, that you should consider doing in the
future (modulo the "Committer testing:" header :) ):

Committer testing:

Before:

  # perf record -e cycles:u
  ^C[ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 1.231 MB perf.data (91 samples) ]
  #
  # perf evlist -v
  cycles:u: size: 120, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, disabled: 1, inherit: 1, exclude_kernel: 1, exclude_hv: 1, freq: 1, sample_id_all: 1
  <SNIP>
  #

After:

  # perf record -e cycles:u
  ^C[ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 1.263 MB perf.data (403 samples) ]
  #
  # perf evlist -v
  cycles:u: size: 120, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ID|CPU|PERIOD, read_format: ID, disabled: 1, inherit: 1, exclude_kernel: 1, exclude_hv: 1, freq: 1, sample_id_all: 1, exclude_guest: 1
  #

----

I.e. show actual command output before and after that demonstrates the
problem and then the solution.

> Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
> ---
>  tools/perf/util/parse-events.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index 9f7260e69113..4d809f1fe269 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -1794,6 +1794,8 @@ static int get_event_modifier(struct event_modifier *mod, char *str,
>  		if (*str == 'u') {
>  			if (!exclude)
>  				exclude = eu = ek = eh = 1;
> +			if (!exclude_GH)
> +				eG = 1;
>  			eu = 0;
>  		} else if (*str == 'k') {
>  			if (!exclude)
> -- 
> 2.17.1
> 

-- 

- Arnaldo