linux-kernel - Re: [PATCH 01/23] perf record: Add --all-user/--all-kernel options

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Date:	Tue, 16 Feb 2016 13:56:01 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Jiri Olsa <jolsa@...nel.org>
Cc:	lkml <linux-kernel@...r.kernel.org>,
	David Ahern <dsahern@...il.com>,
	Ingo Molnar <mingo@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Stephane Eranian <eranian@...gle.com>,
	Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH 01/23] perf record: Add --all-user/--all-kernel options

Em Mon, Feb 15, 2016 at 09:34:31AM +0100, Jiri Olsa escreveu:
> Allow user to easily switch all events to user or
> kernel space with simple --all-user or --all-kernel
> options.
> 
> This will be handy within perf mem/c2c wrappers to
> switch easily monitoring modes.

Humm, some oddities:

  # perf record --all-user -e cycles -a
  # perf report --tui       # And then notice there are some kernel samples, zoom into kernel DSO
  Samples: 7  of event 'cycles', Event count (approx.): 3158810, DSO: [kernel.vmlinux]
  Overhead  Comman  Symbol
    84.05%  chrome  [k] page_fault
    15.73%  chrome  [k] entry_SYSCALL_64
     0.22%  chrome  [k] apic_timer_interrupt

Ditto when using --all-kernel, some userspace samples are there, also perhaps we
should show "cycles:u" or "cycles:k" when this --all-user or --all-kernel features
are used.

Need to investigate why there are kernel samples when --all-user is used and
the other way around as well.

Also if I use both it quietly accepts and shows just one of them, I guess we
should bail out in case someone tries both.

- Arnaldo 

> Link: http://lkml.kernel.org/n/tip-hdd2u0y1o8cwfpplrpzc1iqd@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> ---
>  tools/perf/Documentation/perf-record.txt |  6 ++++++
>  tools/perf/builtin-record.c              |  4 ++++
>  tools/perf/perf.h                        |  2 ++
>  tools/perf/util/evsel.c                  | 10 ++++++++++
>  4 files changed, 22 insertions(+)
> 
> diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
> index fbceb631387c..19aa17532a16 100644
> --- a/tools/perf/Documentation/perf-record.txt
> +++ b/tools/perf/Documentation/perf-record.txt
> @@ -341,6 +341,12 @@ Specify vmlinux path which has debuginfo.
>  --buildid-all::
>  Record build-id of all DSOs regardless whether it's actually hit or not.
>  
> +--all-kernel::
> +Configure all used events to run in kernel space.
> +
> +--all-user::
> +Configure all used events to run in user space.
> +
>  SEE ALSO
>  --------
>  linkperf:perf-stat[1], linkperf:perf-list[1]
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index caa8235ed027..b64f31a4c993 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1151,6 +1151,10 @@ struct option __record_options[] = {
>  			"per thread proc mmap processing timeout in ms"),
>  	OPT_BOOLEAN(0, "switch-events", &record.opts.record_switch_events,
>  		    "Record context switch events"),
> +	OPT_BOOLEAN(0, "all-kernel", &record.opts.all_kernel,
> +		    "Configure all used events to run in kernel space."),
> +	OPT_BOOLEAN(0, "all-user", &record.opts.all_user,
> +		    "Configure all used events to run in user space."),
>  	OPT_STRING(0, "clang-path", &llvm_param.clang_path, "clang path",
>  		   "clang binary to use for compiling BPF scriptlets"),
>  	OPT_STRING(0, "clang-opt", &llvm_param.clang_opt, "clang options",
> diff --git a/tools/perf/perf.h b/tools/perf/perf.h
> index 90129accffbe..5381a01c0610 100644
> --- a/tools/perf/perf.h
> +++ b/tools/perf/perf.h
> @@ -58,6 +58,8 @@ struct record_opts {
>  	bool	     full_auxtrace;
>  	bool	     auxtrace_snapshot_mode;
>  	bool	     record_switch_events;
> +	bool	     all_kernel;
> +	bool	     all_user;
>  	unsigned int freq;
>  	unsigned int mmap_pages;
>  	unsigned int auxtrace_mmap_pages;
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 467808680ee4..6ae20d0056de 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -898,6 +898,16 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts)
>  	if (evsel->precise_max)
>  		perf_event_attr__set_max_precise_ip(attr);
>  
> +	if (opts->all_user) {
> +		attr->exclude_kernel = 1;
> +		attr->exclude_user   = 0;
> +	}
> +
> +	if (opts->all_kernel) {
> +		attr->exclude_kernel = 0;
> +		attr->exclude_user   = 1;
> +	}
> +
>  	/*
>  	 * Apply event specific term settings,
>  	 * it overloads any global configuration.
> -- 
> 2.4.3