[PATCH v2 0/4] Introduce perf check subcommand

[PATCH v2 0/4] Introduce perf check subcommand

[Aditya Gupta]

The Problem
===========

Currently the presence of a feature is checked with a combination of
perf version --build-options and greps, such as:

    perf version --build-options | grep " on .* HAVE_FEATURE"

Proposed solution
=================

As suggested by contributors in:
https://lore.kernel.org/linux-perf-users/ZMPWk5K63tadmDlU@kernel.org/

Introduce a subcommand "perf check --feature", with which
scripts can test for presence of a feature, such as:

    perf check --feature HAVE_LIBTRACEEVENT

    or

    perf check --feature libtraceevent

The usage of "perf version --build-options | grep" has been replaced in two
tests, with "perf check --feature" command

Also, to not duplicate the same feature list at multiple places, a new global
'supported_features' array has been introduced in builtin.h, so both commands
'perf check --feature' and 'perf version --build-options' use the same array

'supported_features' feature is an array of 'struct feature_support', which
also has the name of the feature, macro used to test it's presence, and a
is_builtin member, which will be 0 if feature not built-in, and 1 if built-in

Architectures Tested
====================
* x86_64
* ppc64le

Git tree
========

Git tree with this patch series applied for testing:
https://github.com/adi-g15-ibm/linux/tree/perf-check-feature-v2

Changelog
=========
V2
+ improved the patch series with suggestions from Namhyung
+ fix incorrect return value, added -q option, and moved array definition to
  perf-check.c
V1
+ changed subcommand name to 'perf check --feature'
+ added documentation for perf check
+ support both macro (eg. HAVE_LIBTRACEEVENT), and name (eg. libtraceevent) as
  input to 'perf check --feature'
+ change subject and descriptions of all patch mentioning perf check instead of
  perf build

V0: Previous patch series: https://lore.kernel.org/linux-perf-users/20230825061125.24312-1-adityag@linux.ibm.com/

Aditya Gupta (3):
  perf check: introduce check subcommand
  perf version: update --build-options to use 'supported_features' array
  perf tests task_analyzer: use perf check for libtraceevent support

Athira Rajeev (1):
  tools/perf/tests: Update probe_vfs_getname.sh script to use perf check
    --feature

 tools/perf/Build                              |   1 +
 tools/perf/Documentation/perf-check.txt       |  56 ++++++++
 tools/perf/builtin-check.c                    | 128 ++++++++++++++++++
 tools/perf/builtin-version.c                  |  39 ++----
 tools/perf/builtin.h                          |  18 +++
 tools/perf/perf.c                             |   1 +
 .../perf/tests/shell/lib/probe_vfs_getname.sh |   4 +-
 .../shell/record+probe_libc_inet_pton.sh      |   5 +-
 .../shell/record+script_probe_vfs_getname.sh  |   5 +-
 tools/perf/tests/shell/test_task_analyzer.sh  |   4 +-
 10 files changed, 224 insertions(+), 37 deletions(-)
 create mode 100644 tools/perf/Documentation/perf-check.txt
 create mode 100644 tools/perf/builtin-check.c

-- 
2.41.0

[PATCH v2 1/4] perf check: introduce check subcommand

[Aditya Gupta]

Currently the presence of a feature is checked with a combination of
perf version --build-options and greps, such as:

    perf version --build-options | grep " on .* HAVE_FEATURE"

Instead of this, introduce a subcommand "perf check --feature", with which
scripts can test for presence of a feature, such as:

    perf check --feature HAVE_FEATURE

'perf check --feature' command is expected to have exit status of 1 if feature is
built-in, and 0 if not, -2 if feature is not known.

An array 'supported_features' has also been introduced that can be
used by other commands like 'perf version --build-options', so that
new features can be added in one place, with the array

Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
---
 tools/perf/Build                        |   1 +
 tools/perf/Documentation/perf-check.txt |  56 +++++++++++
 tools/perf/builtin-check.c              | 128 ++++++++++++++++++++++++
 tools/perf/builtin.h                    |  18 ++++
 tools/perf/perf.c                       |   1 +
 5 files changed, 204 insertions(+)
 create mode 100644 tools/perf/Documentation/perf-check.txt
 create mode 100644 tools/perf/builtin-check.c

diff --git a/tools/perf/Build b/tools/perf/Build
index aa7623622834..a55a797c1b5f 100644
--- a/tools/perf/Build
+++ b/tools/perf/Build
@@ -1,5 +1,6 @@
 perf-y += builtin-bench.o
 perf-y += builtin-annotate.o
+perf-y += builtin-check.o
 perf-y += builtin-config.o
 perf-y += builtin-diff.o
 perf-y += builtin-evlist.o
diff --git a/tools/perf/Documentation/perf-check.txt b/tools/perf/Documentation/perf-check.txt
new file mode 100644
index 000000000000..5cf6ab7df8c3
--- /dev/null
+++ b/tools/perf/Documentation/perf-check.txt
@@ -0,0 +1,56 @@
+perf-check(1)
+===============
+
+NAME
+----
+perf-check - check features in perf
+
+SYNOPSIS
+--------
+'perf check' [-q] [--feature]
+
+DESCRIPTION
+-----------
+With no options given, the 'perf check' just prints the perf version
+on the standard output.
+
+If the option '--feature' is given, then status of feature is printed
+on the standard output, ie. whether it is compiled-in/built-in or not
+
+OPTIONS
+-------
+-q::
+		Do not print any messages or warnings
+
+--feature::
+        Print whether a feature is compiled-in or not. A feature name/macro is
+        required to be passed after this flag
+
+        Example Usage:
+                perf check --feature libtraceevent
+                perf check --feature HAVE_LIBTRACEEVENT
+
+        Supported feature names/macro:
+                dwarf      /  HAVE_DWARF_SUPPORT
+                dwarf_getlocations  /  HAVE_DWARF_GETLOCATIONS_SUPPORT
+                libaudit   /  HAVE_LIBAUDIT_SUPPORT
+                syscall_table       /  HAVE_SYSCALL_TABLE_SUPPORT
+                libbfd     /  HAVE_LIBBFD_SUPPORT
+                debuginfod /  HAVE_DEBUGINFOD_SUPPORT
+                libelf     /  HAVE_LIBELF_SUPPORT
+                libnuma    /  HAVE_LIBNUMA_SUPPORT
+                numa_num_possible_cpus  /  HAVE_LIBNUMA_SUPPORT
+                libperl    /  HAVE_LIBPERL_SUPPORT
+                libpython  /  HAVE_LIBPYTHON_SUPPORT
+                libslang   /  HAVE_SLANG_SUPPORT
+                libcrypto  /  HAVE_LIBCRYPTO_SUPPORT
+                libunwind  /  HAVE_LIBUNWIND_SUPPORT
+                libdw-dwarf-unwind  /  HAVE_DWARF_SUPPORT
+                zlib       /  HAVE_ZLIB_SUPPORT
+                lzma       /  HAVE_LZMA_SUPPORT
+                get_cpuid  /  HAVE_AUXTRACE_SUPPORT
+                bpf        /  HAVE_LIBBPF_SUPPORT
+                aio        /  HAVE_AIO_SUPPORT
+                zstd       /  HAVE_ZSTD_SUPPORT
+                libpfm4    /  HAVE_LIBPFM
+                libtraceevent      /  HAVE_LIBTRACEEVENT
diff --git a/tools/perf/builtin-check.c b/tools/perf/builtin-check.c
new file mode 100644
index 000000000000..acd0cfe135d4
--- /dev/null
+++ b/tools/perf/builtin-check.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "builtin.h"
+#include "color.h"
+#include "util/debug.h"
+#include "util/header.h"
+#include <tools/config.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <subcmd/parse-options.h>
+
+struct check {
+	const char *feature;
+};
+
+static struct check check;
+
+static struct option check_options[] = {
+	OPT_STRING(0, "feature", &check.feature, NULL, "check if a feature is built in"),
+	OPT_BOOLEAN('q', "quiet", &quiet, "do not show any warnings or messages"),
+	OPT_END(),
+};
+
+static const char * const check_usage[] = {
+	"perf check [<options>]",
+	NULL
+};
+
+struct feature_support supported_features[] = {
+	FEATURE_SUPPORT("dwarf", HAVE_DWARF_SUPPORT),
+	FEATURE_SUPPORT("dwarf_getlocations", HAVE_DWARF_GETLOCATIONS_SUPPORT),
+	FEATURE_SUPPORT("libaudit", HAVE_LIBAUDIT_SUPPORT),
+	FEATURE_SUPPORT("syscall_table", HAVE_SYSCALL_TABLE_SUPPORT),
+	FEATURE_SUPPORT("libbfd", HAVE_LIBBFD_SUPPORT),
+	FEATURE_SUPPORT("debuginfod", HAVE_DEBUGINFOD_SUPPORT),
+	FEATURE_SUPPORT("libelf", HAVE_LIBELF_SUPPORT),
+	FEATURE_SUPPORT("libnuma", HAVE_LIBNUMA_SUPPORT),
+	FEATURE_SUPPORT("numa_num_possible_cpus", HAVE_LIBNUMA_SUPPORT),
+	FEATURE_SUPPORT("libperl", HAVE_LIBPERL_SUPPORT),
+	FEATURE_SUPPORT("libpython", HAVE_LIBPYTHON_SUPPORT),
+	FEATURE_SUPPORT("libslang", HAVE_SLANG_SUPPORT),
+	FEATURE_SUPPORT("libcrypto", HAVE_LIBCRYPTO_SUPPORT),
+	FEATURE_SUPPORT("libunwind", HAVE_LIBUNWIND_SUPPORT),
+	FEATURE_SUPPORT("libdw-dwarf-unwind", HAVE_DWARF_SUPPORT),
+	FEATURE_SUPPORT("zlib", HAVE_ZLIB_SUPPORT),
+	FEATURE_SUPPORT("lzma", HAVE_LZMA_SUPPORT),
+	FEATURE_SUPPORT("get_cpuid", HAVE_AUXTRACE_SUPPORT),
+	FEATURE_SUPPORT("bpf", HAVE_LIBBPF_SUPPORT),
+	FEATURE_SUPPORT("aio", HAVE_AIO_SUPPORT),
+	FEATURE_SUPPORT("zstd", HAVE_ZSTD_SUPPORT),
+	FEATURE_SUPPORT("libpfm4", HAVE_LIBPFM),
+	FEATURE_SUPPORT("libtraceevent", HAVE_LIBTRACEEVENT),
+
+	// this should remain at end, to know the array end
+	FEATURE_SUPPORT(NULL, _)
+};
+
+static void on_off_print(const char *status)
+{
+	printf("[ ");
+
+	if (!strcmp(status, "OFF"))
+		color_fprintf(stdout, PERF_COLOR_RED, "%-3s", status);
+	else
+		color_fprintf(stdout, PERF_COLOR_GREEN, "%-3s", status);
+
+	printf(" ]");
+}
+
+static void status_print(const char *name, const char *macro,
+			 const char *status)
+{
+	printf("%22s: ", name);
+	on_off_print(status);
+	printf("  # %s\n", macro);
+}
+
+#define STATUS(feature)                                   \
+do {                                                      \
+	if (feature.is_builtin)                               \
+		status_print(feature.name, feature.macro, "on");  \
+	else                                                  \
+		status_print(feature.name, feature.macro, "OFF"); \
+} while (0)
+
+/**
+ * check whether "feature" is built-in with perf
+ * returns:
+ *   -1: Feature not known
+ *    0: Built-in
+ *    1: NOT Built in
+ */
+static int has_support(const char *feature)
+{
+	int res = -1;
+
+	for (int i = 0; supported_features[i].name; ++i) {
+		if ((strcmp(feature, supported_features[i].name) == 0) ||
+			(strcmp(feature, supported_features[i].macro) == 0)) {
+			res = supported_features[i].is_builtin;
+			if (!quiet)
+				STATUS(supported_features[i]);
+			break;
+		}
+	}
+
+	if (res == -1) {
+		if (!quiet)
+			color_fprintf(stdout, PERF_COLOR_RED, "Feature not known: %s", feature);
+		return -1;
+	}
+
+	return !res;
+}
+
+int cmd_check(int argc, const char **argv)
+{
+	argc = parse_options(argc, argv, check_options, check_usage,
+			     PARSE_OPT_STOP_AT_NON_OPTION);
+
+	if (!quiet)
+		printf("perf check %s\n", perf_version_string);
+
+	if (check.feature)
+		return has_support(check.feature);
+
+	return 0;
+}
diff --git a/tools/perf/builtin.h b/tools/perf/builtin.h
index f2ab5bae2150..9f895981bc9e 100644
--- a/tools/perf/builtin.h
+++ b/tools/perf/builtin.h
@@ -2,6 +2,23 @@
 #ifndef BUILTIN_H
 #define BUILTIN_H
 
+#include <stddef.h>
+#include <linux/compiler.h>
+#include <tools/config.h>
+
+struct feature_support {
+	const char *name;
+	const char *macro;
+	int is_builtin;
+};
+
+#define FEATURE_SUPPORT(name_, macro_) { \
+	.name = name_,                       \
+	.macro = #macro_,                    \
+	.is_builtin = IS_BUILTIN(macro_) }
+
+extern struct feature_support supported_features[];
+
 void list_common_cmds_help(void);
 const char *help_unknown_cmd(const char *cmd);
 
@@ -9,6 +26,7 @@ int cmd_annotate(int argc, const char **argv);
 int cmd_bench(int argc, const char **argv);
 int cmd_buildid_cache(int argc, const char **argv);
 int cmd_buildid_list(int argc, const char **argv);
+int cmd_check(int argc, const char **argv);
 int cmd_config(int argc, const char **argv);
 int cmd_c2c(int argc, const char **argv);
 int cmd_diff(int argc, const char **argv);
diff --git a/tools/perf/perf.c b/tools/perf/perf.c
index d3fc8090413c..83dc0ac42fdb 100644
--- a/tools/perf/perf.c
+++ b/tools/perf/perf.c
@@ -50,6 +50,7 @@ static struct cmd_struct commands[] = {
 	{ "archive",	NULL,	0 },
 	{ "buildid-cache", cmd_buildid_cache, 0 },
 	{ "buildid-list", cmd_buildid_list, 0 },
+	{ "check", cmd_check, 0 },
 	{ "config",	cmd_config,	0 },
 	{ "c2c",	cmd_c2c,	0 },
 	{ "diff",	cmd_diff,	0 },
-- 
2.41.0

[PATCH v2 2/4] perf version: update --build-options to use 'supported_features' array

[Aditya Gupta]

Now that the feature list has been duplicated in a global
'supported_features' array, use that array instead of manually checking
status of built-in features.

This helps in being consistent with commands such as 'perf check --feature',
so commands can use the same array, and any new feature can be added at
one place, in the 'supported_features' array

Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
---
 tools/perf/builtin-version.c | 39 ++++++++----------------------------
 1 file changed, 8 insertions(+), 31 deletions(-)

diff --git a/tools/perf/builtin-version.c b/tools/perf/builtin-version.c
index e5859c70e195..e149d96c6dc5 100644
--- a/tools/perf/builtin-version.c
+++ b/tools/perf/builtin-version.c
@@ -46,41 +46,18 @@ static void status_print(const char *name, const char *macro,
 	printf("  # %s\n", macro);
 }
 
-#define STATUS(__d, __m)				\
-do {							\
-	if (IS_BUILTIN(__d))				\
-		status_print(#__m, #__d, "on");		\
-	else						\
-		status_print(#__m, #__d, "OFF");	\
+#define STATUS(feature)                                   \
+do {                                                      \
+	if (feature.is_builtin)                               \
+		status_print(feature.name, feature.macro, "on");  \
+	else                                                  \
+		status_print(feature.name, feature.macro, "OFF"); \
 } while (0)
 
 static void library_status(void)
 {
-	STATUS(HAVE_DWARF_SUPPORT, dwarf);
-	STATUS(HAVE_DWARF_GETLOCATIONS_SUPPORT, dwarf_getlocations);
-#ifndef HAVE_SYSCALL_TABLE_SUPPORT
-	STATUS(HAVE_LIBAUDIT_SUPPORT, libaudit);
-#endif
-	STATUS(HAVE_SYSCALL_TABLE_SUPPORT, syscall_table);
-	STATUS(HAVE_LIBBFD_SUPPORT, libbfd);
-	STATUS(HAVE_DEBUGINFOD_SUPPORT, debuginfod);
-	STATUS(HAVE_LIBELF_SUPPORT, libelf);
-	STATUS(HAVE_LIBNUMA_SUPPORT, libnuma);
-	STATUS(HAVE_LIBNUMA_SUPPORT, numa_num_possible_cpus);
-	STATUS(HAVE_LIBPERL_SUPPORT, libperl);
-	STATUS(HAVE_LIBPYTHON_SUPPORT, libpython);
-	STATUS(HAVE_SLANG_SUPPORT, libslang);
-	STATUS(HAVE_LIBCRYPTO_SUPPORT, libcrypto);
-	STATUS(HAVE_LIBUNWIND_SUPPORT, libunwind);
-	STATUS(HAVE_DWARF_SUPPORT, libdw-dwarf-unwind);
-	STATUS(HAVE_ZLIB_SUPPORT, zlib);
-	STATUS(HAVE_LZMA_SUPPORT, lzma);
-	STATUS(HAVE_AUXTRACE_SUPPORT, get_cpuid);
-	STATUS(HAVE_LIBBPF_SUPPORT, bpf);
-	STATUS(HAVE_AIO_SUPPORT, aio);
-	STATUS(HAVE_ZSTD_SUPPORT, zstd);
-	STATUS(HAVE_LIBPFM, libpfm4);
-	STATUS(HAVE_LIBTRACEEVENT, libtraceevent);
+	for (int i = 0; supported_features[i].name; ++i)
+		STATUS(supported_features[i]);
 }
 
 int cmd_version(int argc, const char **argv)
-- 
2.41.0

[PATCH v2 3/4] perf tests task_analyzer: use perf check for libtraceevent support

[Aditya Gupta]

Currently we use output of 'perf version --build-options', to check whether
perf was built with libtraceevent support.

Instead, use 'perf check --feature libtraceevent' to check for
libtraceevent support.

Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
---
 tools/perf/tests/shell/test_task_analyzer.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/tests/shell/test_task_analyzer.sh b/tools/perf/tests/shell/test_task_analyzer.sh
index 92d15154ba79..f4db68edb2e3 100755
--- a/tools/perf/tests/shell/test_task_analyzer.sh
+++ b/tools/perf/tests/shell/test_task_analyzer.sh
@@ -52,8 +52,8 @@ find_str_or_fail() {
 
 # check if perf is compiled with libtraceevent support
 skip_no_probe_record_support() {
-	perf version --build-options | grep -q " OFF .* HAVE_LIBTRACEEVENT" && return 2
-	return 0
+	perf check -q --feature libtraceevent && return 0
+	return 2
 }
 
 prepare_perf_data() {
-- 
2.41.0

[PATCH v2 4/4] tools/perf/tests: Update probe_vfs_getname.sh script to use perf check --feature

[Aditya Gupta]

From: Athira Rajeev <atrajeev@linux.vnet.ibm.com>

In probe_vfs_getname.sh, current we use "perf record --dry-run"
to check for libtraceevent and skip the test if perf is not
build with libtraceevent. Change the check to use "perf check --feature"
option

Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
---
 tools/perf/tests/shell/lib/probe_vfs_getname.sh           | 4 ++--
 tools/perf/tests/shell/record+probe_libc_inet_pton.sh     | 5 ++++-
 tools/perf/tests/shell/record+script_probe_vfs_getname.sh | 5 ++++-
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/tools/perf/tests/shell/lib/probe_vfs_getname.sh b/tools/perf/tests/shell/lib/probe_vfs_getname.sh
index bf4c1fb71c4b..368a55c02134 100644
--- a/tools/perf/tests/shell/lib/probe_vfs_getname.sh
+++ b/tools/perf/tests/shell/lib/probe_vfs_getname.sh
@@ -27,7 +27,7 @@ skip_if_no_debuginfo() {
 # check if perf is compiled with libtraceevent support
 skip_no_probe_record_support() {
 	if [ $had_vfs_getname -eq 1 ] ; then
-		perf record --dry-run -e $1 2>&1 | grep "libtraceevent is necessary for tracepoint support" && return 2
-		return 1
+		perf check -q --feature libtraceevent && return 1
+		return 2
 	fi
 }
diff --git a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
index 89214a6d9951..0c00e94b83ff 100755
--- a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
+++ b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
@@ -58,7 +58,10 @@ trace_libc_inet_pton_backtrace() {
 
 	# Check presence of libtraceevent support to run perf record
 	skip_no_probe_record_support "$event_name/$eventattr/"
-	[ $? -eq 2 ] && return 2
+	if [ $? -eq 2 ]; then
+		echo "WARN: Skipping test trace_libc_inet_pton_backtrace. No libtraceevent support."
+		return 2
+	fi
 
 	perf record -e $event_name/$eventattr/ -o $perf_data ping -6 -c 1 ::1 > /dev/null 2>&1
 	# check if perf data file got created in above step.
diff --git a/tools/perf/tests/shell/record+script_probe_vfs_getname.sh b/tools/perf/tests/shell/record+script_probe_vfs_getname.sh
index 7f664f1889d9..c7416d21fc92 100755
--- a/tools/perf/tests/shell/record+script_probe_vfs_getname.sh
+++ b/tools/perf/tests/shell/record+script_probe_vfs_getname.sh
@@ -19,7 +19,10 @@ record_open_file() {
 	echo "Recording open file:"
 	# Check presence of libtraceevent support to run perf record
 	skip_no_probe_record_support "probe:vfs_getname*"
-	[ $? -eq 2 ] && return 2
+	if [ $? -eq 2 ]; then
+		echo "WARN: Skipping test record_open_file. No libtraceevent support"
+		return 2
+	fi
 	perf record -o ${perfdata} -e probe:vfs_getname\* touch $file
 }
 
-- 
2.41.0

Re: [PATCH v2 1/4] perf check: introduce check subcommand

[Namhyung Kim]

Hello,

On Wed, Sep 20, 2023 at 12:29 PM Aditya Gupta <adityag@linux.ibm.com> wrote:
>
> Currently the presence of a feature is checked with a combination of
> perf version --build-options and greps, such as:
>
>     perf version --build-options | grep " on .* HAVE_FEATURE"
>
> Instead of this, introduce a subcommand "perf check --feature", with which
> scripts can test for presence of a feature, such as:
>
>     perf check --feature HAVE_FEATURE
>
> 'perf check --feature' command is expected to have exit status of 1 if feature is
> built-in, and 0 if not, -2 if feature is not known.
>
> An array 'supported_features' has also been introduced that can be
> used by other commands like 'perf version --build-options', so that
> new features can be added in one place, with the array
>
> Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
> ---

[SNIP]
> +/**
> + * check whether "feature" is built-in with perf
> + * returns:
> + *   -1: Feature not known
> + *    0: Built-in
> + *    1: NOT Built in

It seems not intuitive.  I'd return 1 if it's builtin.
Maybe we can return 0 for unknown ones too.

> + */
> +static int has_support(const char *feature)
> +{
> +       int res = -1;
> +
> +       for (int i = 0; supported_features[i].name; ++i) {
> +               if ((strcmp(feature, supported_features[i].name) == 0) ||
> +                       (strcmp(feature, supported_features[i].macro) == 0)) {

Please align it to the previous strcmp().


> +                       res = supported_features[i].is_builtin;
> +                       if (!quiet)
> +                               STATUS(supported_features[i]);
> +                       break;

Why not return right here?


> +               }
> +       }
> +
> +       if (res == -1) {
> +               if (!quiet)
> +                       color_fprintf(stdout, PERF_COLOR_RED, "Feature not known: %s", feature);
> +               return -1;
> +       }

Then you don't even need the 'res' variable.

> +
> +       return !res;
> +}
> +
> +int cmd_check(int argc, const char **argv)
> +{
> +       argc = parse_options(argc, argv, check_options, check_usage,
> +                            PARSE_OPT_STOP_AT_NON_OPTION);
> +
> +       if (!quiet)
> +               printf("perf check %s\n", perf_version_string);
> +
> +       if (check.feature)
> +               return has_support(check.feature);
> +
> +       return 0;
> +}
> diff --git a/tools/perf/builtin.h b/tools/perf/builtin.h
> index f2ab5bae2150..9f895981bc9e 100644
> --- a/tools/perf/builtin.h
> +++ b/tools/perf/builtin.h
> @@ -2,6 +2,23 @@
>  #ifndef BUILTIN_H
>  #define BUILTIN_H
>
> +#include <stddef.h>
> +#include <linux/compiler.h>
> +#include <tools/config.h>
> +
> +struct feature_support {
> +       const char *name;
> +       const char *macro;
> +       int is_builtin;
> +};
> +
> +#define FEATURE_SUPPORT(name_, macro_) { \
> +       .name = name_,                       \
> +       .macro = #macro_,                    \
> +       .is_builtin = IS_BUILTIN(macro_) }
> +
> +extern struct feature_support supported_features[];
> +
>  void list_common_cmds_help(void);
>  const char *help_unknown_cmd(const char *cmd);
>
> @@ -9,6 +26,7 @@ int cmd_annotate(int argc, const char **argv);
>  int cmd_bench(int argc, const char **argv);
>  int cmd_buildid_cache(int argc, const char **argv);
>  int cmd_buildid_list(int argc, const char **argv);
> +int cmd_check(int argc, const char **argv);
>  int cmd_config(int argc, const char **argv);
>  int cmd_c2c(int argc, const char **argv);
>  int cmd_diff(int argc, const char **argv);
> diff --git a/tools/perf/perf.c b/tools/perf/perf.c
> index d3fc8090413c..83dc0ac42fdb 100644
> --- a/tools/perf/perf.c
> +++ b/tools/perf/perf.c
> @@ -50,6 +50,7 @@ static struct cmd_struct commands[] = {
>         { "archive",    NULL,   0 },
>         { "buildid-cache", cmd_buildid_cache, 0 },
>         { "buildid-list", cmd_buildid_list, 0 },
> +       { "check", cmd_check, 0 },

Please align this.

Thanks,
Namhyung


>         { "config",     cmd_config,     0 },
>         { "c2c",        cmd_c2c,        0 },
>         { "diff",       cmd_diff,       0 },
> --
> 2.41.0
>

Re: [PATCH v2 1/4] perf check: introduce check subcommand

[Aditya Gupta]

Hi Namhyung,
Thanks for the reviews. Also, sorry for the delays in my replies.

On Tue, Sep 26, 2023 at 05:29:35PM -0700, Namhyung Kim wrote:
> Hello,
> 
> On Wed, Sep 20, 2023 at 12:29 PM Aditya Gupta <adityag@linux.ibm.com> wrote:
> >
> > Currently the presence of a feature is checked with a combination of
> > perf version --build-options and greps, such as:
> >
> >     perf version --build-options | grep " on .* HAVE_FEATURE"
> >
> > Instead of this, introduce a subcommand "perf check --feature", with which
> > scripts can test for presence of a feature, such as:
> >
> >     perf check --feature HAVE_FEATURE
> >
> > 'perf check --feature' command is expected to have exit status of 1 if feature is
> > built-in, and 0 if not, -2 if feature is not known.
> >
> > An array 'supported_features' has also been introduced that can be
> > used by other commands like 'perf version --build-options', so that
> > new features can be added in one place, with the array
> >
> > Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
> > ---
> 
> [SNIP]
> > +/**
> > + * check whether "feature" is built-in with perf
> > + * returns:
> > + *   -1: Feature not known
> > + *    0: Built-in
> > + *    1: NOT Built in
> 
> It seems not intuitive.  I'd return 1 if it's builtin.

Yes, initially it used to return 1 (TRUE) if builtin, 0 if not (FALSE).
The idea was that scripts were using 'grep "HAVE_FEATURE" && return 1', so to
match the grep behaviour (if search is true, it returns 0), I changed it.

That said, I do agree with your intuitive point, will change it back in V3.

> Maybe we can return 0 for unknown ones too.

Sure, that also removes the need for 'res' as you suggested later.

> 
> > + */
> > +static int has_support(const char *feature)
> > +{
> > +       int res = -1;
> > +
> > +       for (int i = 0; supported_features[i].name; ++i) {
> > +               if ((strcmp(feature, supported_features[i].name) == 0) ||
> > +                       (strcmp(feature, supported_features[i].macro) == 0)) {
> 
> Please align it to the previous strcmp().

Oh sorry, missed it as it was showing aligned for me (due to tab). Will align it
in V3.

> 
> 
> > +                       res = supported_features[i].is_builtin;
> > +                       if (!quiet)
> > +                               STATUS(supported_features[i]);
> > +                       break;
> 
> Why not return right here?

Sure, can return here.

> 
> 
> > +               }
> > +       }
> > +
> > +       if (res == -1) {
> > +               if (!quiet)
> > +                       color_fprintf(stdout, PERF_COLOR_RED, "Feature not known: %s", feature);
> > +               return -1;
> > +       }
> 
> Then you don't even need the 'res' variable.

Yup, with the -1 and 0 both be 0, I will remove the 'res'.

> 
> > +
> > +       return !res;
> > +}
> > +
> > +int cmd_check(int argc, const char **argv)
> > +{
> > +       argc = parse_options(argc, argv, check_options, check_usage,
> > +                            PARSE_OPT_STOP_AT_NON_OPTION);
> > +
> > +       if (!quiet)
> > +               printf("perf check %s\n", perf_version_string);
> > +
> > +       if (check.feature)
> > +               return has_support(check.feature);
> > +
> > +       return 0;
> > +}
> > diff --git a/tools/perf/builtin.h b/tools/perf/builtin.h
> > index f2ab5bae2150..9f895981bc9e 100644
> > --- a/tools/perf/builtin.h
> > +++ b/tools/perf/builtin.h
> > @@ -2,6 +2,23 @@
> >  #ifndef BUILTIN_H
> >  #define BUILTIN_H
> >
> > +#include <stddef.h>
> > +#include <linux/compiler.h>
> > +#include <tools/config.h>
> > +
> > +struct feature_support {
> > +       const char *name;
> > +       const char *macro;
> > +       int is_builtin;
> > +};
> > +
> > +#define FEATURE_SUPPORT(name_, macro_) { \
> > +       .name = name_,                       \
> > +       .macro = #macro_,                    \
> > +       .is_builtin = IS_BUILTIN(macro_) }
> > +
> > +extern struct feature_support supported_features[];
> > +
> >  void list_common_cmds_help(void);
> >  const char *help_unknown_cmd(const char *cmd);
> >
> > @@ -9,6 +26,7 @@ int cmd_annotate(int argc, const char **argv);
> >  int cmd_bench(int argc, const char **argv);
> >  int cmd_buildid_cache(int argc, const char **argv);
> >  int cmd_buildid_list(int argc, const char **argv);
> > +int cmd_check(int argc, const char **argv);
> >  int cmd_config(int argc, const char **argv);
> >  int cmd_c2c(int argc, const char **argv);
> >  int cmd_diff(int argc, const char **argv);
> > diff --git a/tools/perf/perf.c b/tools/perf/perf.c
> > index d3fc8090413c..83dc0ac42fdb 100644
> > --- a/tools/perf/perf.c
> > +++ b/tools/perf/perf.c
> > @@ -50,6 +50,7 @@ static struct cmd_struct commands[] = {
> >         { "archive",    NULL,   0 },
> >         { "buildid-cache", cmd_buildid_cache, 0 },
> >         { "buildid-list", cmd_buildid_list, 0 },
> > +       { "check", cmd_check, 0 },
> 
> Please align this.

It should be aligned, on my system it's showing one tab before this, as the
other lines also do, will align it in next version.

Also namhyung, I moved the definition of the 'supported_features' array to
builtin-check.c, and is also accessed in builtin-version.c does that seem good
to you ?

Thanks,
- Aditya Gupta

> 
> Thanks,
> Namhyung
> 
> 
> >         { "config",     cmd_config,     0 },
> >         { "c2c",        cmd_c2c,        0 },
> >         { "diff",       cmd_diff,       0 },
> > --
> > 2.41.0
> >

Re: [PATCH v2 1/4] perf check: introduce check subcommand

[Namhyung Kim]

On Wed, Sep 27, 2023 at 3:18 AM Aditya Gupta <adityag@linux.ibm.com> wrote:
> Also namhyung, I moved the definition of the 'supported_features' array to
> builtin-check.c, and is also accessed in builtin-version.c does that seem good
> to you ?

Yeah, I liked that part :)

Thanks,
Namhyung