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From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Riccardo Mancini <rickyman7@gmail.com>
Cc: Ian Rogers <irogers@google.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>, Jiri Olsa <jolsa@redhat.com>,
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Subject: Re: [RFC PATCH v1 24/37] perf evsel: handle precise_ip fallback in evsel__open_cpu
Date: Tue, 31 Aug 2021 16:52:48 -0300	[thread overview]
Message-ID: <YS6IkHuMDIGuOzO7@kernel.org> (raw)
In-Reply-To: <74208c433d2024a6c4af9c0b140b54ed6b5ea810.1629490974.git.rickyman7@gmail.com>

Em Sat, Aug 21, 2021 at 11:19:30AM +0200, Riccardo Mancini escreveu:
> This is another patch in the effort to separate the fallback mechanisms
> from the open itself.
> 
> In case of precise_ip fallback, the original precise_ip will be stored
> in the evsel (it was stored in a local variable) and the open will be
> retried. Since the precise_ip fallback will be the first in the chain of
> fallbacks, there should be no functional change with this patch.

Thanks, looks ok, applied.

- Arnaldo

 
> Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
> ---
>  tools/perf/util/evsel.c | 59 ++++++++++++++++++-----------------------
>  tools/perf/util/evsel.h |  2 ++
>  2 files changed, 28 insertions(+), 33 deletions(-)
> 
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 3e556afed8dd396c..2e95416b8320c6b9 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -1709,42 +1709,29 @@ static void display_attr(struct perf_event_attr *attr)
>  	}
>  }
>  
> -static int perf_event_open(struct evsel *evsel,
> -			   pid_t pid, int cpu, int group_fd)
> +bool evsel__precise_ip_fallback(struct evsel *evsel)
>  {
> -	int precise_ip = evsel->core.attr.precise_ip;
> -	int fd;
> -
> -	while (1) {
> -		pr_debug2_peo("sys_perf_event_open: pid %d  cpu %d  group_fd %d  flags %#lx",
> -			  pid, cpu, group_fd, evsel->open_flags);
> -
> -		fd = sys_perf_event_open(&evsel->core.attr, pid, cpu, group_fd, evsel->open_flags);
> -		if (fd >= 0)
> -			break;
> -
> -		/* Do not try less precise if not requested. */
> -		if (!evsel->precise_max)
> -			break;
> -
> -		/*
> -		 * We tried all the precise_ip values, and it's
> -		 * still failing, so leave it to standard fallback.
> -		 */
> -		if (!evsel->core.attr.precise_ip) {
> -			evsel->core.attr.precise_ip = precise_ip;
> -			break;
> -		}
> +	/* Do not try less precise if not requested. */
> +	if (!evsel->precise_max)
> +		return false;
>  
> -		pr_debug2_peo("\nsys_perf_event_open failed, error %d\n", -ENOTSUP);
> -		evsel->core.attr.precise_ip--;
> -		pr_debug2_peo("decreasing precise_ip by one (%d)\n", evsel->core.attr.precise_ip);
> -		display_attr(&evsel->core.attr);
> +	/*
> +	 * We tried all the precise_ip values, and it's
> +	 * still failing, so leave it to standard fallback.
> +	 */
> +	if (!evsel->core.attr.precise_ip) {
> +		evsel->core.attr.precise_ip = evsel->precise_ip_original;
> +		return false;
>  	}
>  
> -	return fd;
> -}
> +	if (!evsel->precise_ip_original)
> +		evsel->precise_ip_original = evsel->core.attr.precise_ip;
>  
> +	evsel->core.attr.precise_ip--;
> +	pr_debug2_peo("decreasing precise_ip by one (%d)\n", evsel->core.attr.precise_ip);
> +	display_attr(&evsel->core.attr);
> +	return true;
> +}
>  
>  static struct perf_cpu_map *empty_cpu_map;
>  static struct perf_thread_map *empty_thread_map;
> @@ -2004,8 +1991,11 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
>  
>  			test_attr__ready();
>  
> -			fd = perf_event_open(evsel, pid, cpus->map[cpu],
> -					     group_fd);
> +			pr_debug2_peo("sys_perf_event_open: pid %d  cpu %d  group_fd %d  flags %#lx",
> +				pid, cpus->map[cpu], group_fd, evsel->open_flags);
> +
> +			fd = sys_perf_event_open(&evsel->core.attr, pid, cpus->map[cpu],
> +						group_fd, evsel->open_flags);
>  
>  			FD(evsel, cpu, thread) = fd;
>  
> @@ -2058,6 +2048,9 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
>  	return 0;
>  
>  try_fallback:
> +	if (evsel__precise_ip_fallback(evsel))
> +		goto retry_open;
> +
>  	if (evsel__ignore_missing_thread(evsel, cpus->nr, cpu, threads, thread, err)) {
>  		/* We just removed 1 thread, so lower the upper nthreads limit. */
>  		nthreads--;
> diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
> index 661d2677a19b6248..0a245afab2d87d74 100644
> --- a/tools/perf/util/evsel.h
> +++ b/tools/perf/util/evsel.h
> @@ -150,6 +150,7 @@ struct evsel {
>  		struct bperf_follower_bpf *follower_skel;
>  	};
>  	unsigned long		open_flags;
> +	int			precise_ip_original;
>  };
>  
>  struct perf_missing_features {
> @@ -297,6 +298,7 @@ bool evsel__ignore_missing_thread(struct evsel *evsel,
>  				  int nr_cpus, int cpu,
>  				  struct perf_thread_map *threads,
>  				  int thread, int err);
> +bool evsel__precise_ip_fallback(struct evsel *evsel);
>  
>  struct perf_sample;
>  
> -- 
> 2.31.1

-- 

- Arnaldo

  reply	other threads:[~2021-08-31 19:52 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-21  9:19 [RFC PATCH v1 00/37] perf: use workqueue for evlist operations Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 01/37] libperf cpumap: improve idx function Riccardo Mancini
2021-08-31 18:46   ` Arnaldo Carvalho de Melo
2021-10-08 14:29   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 02/37] libperf cpumap: improve max function Riccardo Mancini
2021-08-31 18:47   ` Arnaldo Carvalho de Melo
2021-08-31 19:16     ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 03/37] perf evlist: replace evsel__cpu_iter* functions with evsel__find_cpu Riccardo Mancini
2021-10-08 14:38   ` [RFC PATCH v1 03/37] perf evlist: replace evsel__cpu_iter* functions with evsel__find_cpu() Arnaldo Carvalho de Melo
2021-12-11  0:20   ` [RFC PATCH v1 03/37] perf evlist: replace evsel__cpu_iter* functions with evsel__find_cpu Ian Rogers
2021-08-21  9:19 ` [RFC PATCH v1 04/37] perf util: add mmap_cpu_mask__duplicate function Riccardo Mancini
2021-08-31 19:21   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 05/37] perf util/mmap: add missing bitops.h header Riccardo Mancini
2021-08-31 19:22   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 06/37] perf workqueue: add affinities to threadpool Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 07/37] perf workqueue: add support for setting affinities to workers Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 08/37] perf workqueue: add method to execute work on specific CPU Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 09/37] perf python: add workqueue dependency Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 10/37] perf evlist: add multithreading helper Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 11/37] perf evlist: add multithreading to evlist__disable Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 12/37] perf evlist: add multithreading to evlist__enable Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 13/37] perf evlist: add multithreading to evlist__close Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 14/37] perf evsel: remove retry_sample_id goto label Riccardo Mancini
2021-08-31 19:25   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 15/37] perf evsel: separate open preparation from open itself Riccardo Mancini
2021-08-31 19:27   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 16/37] perf evsel: save open flags in evsel Riccardo Mancini
2021-08-31 19:31   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 17/37] perf evsel: separate missing feature disabling from evsel__open_cpu Riccardo Mancini
2021-08-31 19:35   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 18/37] perf evsel: add evsel__prepare_open function Riccardo Mancini
2021-08-31 19:36   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 19/37] perf evsel: separate missing feature detection from evsel__open_cpu Riccardo Mancini
2021-08-31 19:39   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 20/37] perf evsel: separate rlimit increase " Riccardo Mancini
2021-08-31 19:41   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 21/37] perf evsel: move ignore_missing_thread to fallback code Riccardo Mancini
2021-08-31 19:44   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 22/37] perf evsel: move test_attr__open to success path in evsel__open_cpu Riccardo Mancini
2021-08-31 19:47   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 23/37] perf evsel: move bpf_counter__install_pe " Riccardo Mancini
2021-08-31 19:50   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 24/37] perf evsel: handle precise_ip fallback " Riccardo Mancini
2021-08-31 19:52   ` Arnaldo Carvalho de Melo [this message]
2021-08-21  9:19 ` [RFC PATCH v1 25/37] perf evsel: move event open in evsel__open_cpu to separate function Riccardo Mancini
2021-08-31 19:54   ` Arnaldo Carvalho de Melo
2021-09-03 21:52     ` Riccardo Mancini
2021-09-11 19:10       ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 26/37] perf evsel: add evsel__open_per_cpu_no_fallback function Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 27/37] perf evlist: add evlist__for_each_entry_from macro Riccardo Mancini
2021-08-31 20:06   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 28/37] perf evlist: add multithreading to evlist__open Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 29/37] perf evlist: add custom fallback " Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 30/37] perf record: use evlist__open_custom Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 31/37] tools lib/subcmd: add OPT_UINTEGER_OPTARG option type Riccardo Mancini
2021-08-31 18:44   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 32/37] perf record: add --threads option Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 33/37] perf record: pin threads to monitored cpus if enough threads available Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 34/37] perf record: apply multithreading in init and fini phases Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 35/37] perf test/evlist-open-close: add multithreading Riccardo Mancini
2021-08-21  9:19 ` [RFC PATCH v1 36/37] perf test/evlist-open-close: use inline func to convert timeval to usec Riccardo Mancini
2021-10-08 14:46   ` Arnaldo Carvalho de Melo
2021-08-21  9:19 ` [RFC PATCH v1 37/37] perf test/evlist-open-close: add detailed output mode Riccardo Mancini

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