[PATCH v10 1/4] lib: add generic support for reading PMU events

[Ruifeng Wang]

> -----Original Message-----
> From: Tomasz Duszynski <tduszynski at marvell.com>
> Sent: Monday, February 13, 2023 7:32 PM
> To: dev at dpdk.org; thomas at monjalon.net; Tomasz Duszynski <tduszynski at marvell.com>
> Cc: roretzla at linux.microsoft.com; Ruifeng Wang <Ruifeng.Wang at arm.com>;
> bruce.richardson at intel.com; jerinj at marvell.com; mattias.ronnblom at ericsson.com;
> mb at smartsharesystems.com; zhoumin at loongson.cn; david.marchand at redhat.com
> Subject: [PATCH v10 1/4] lib: add generic support for reading PMU events
> 
> Add support for programming PMU counters and reading their values in runtime bypassing
> kernel completely.
> 
> This is especially useful in cases where CPU cores are isolated i.e run dedicated tasks.
> In such cases one cannot use standard perf utility without sacrificing latency and
> performance.
> 
> Signed-off-by: Tomasz Duszynski <tduszynski at marvell.com>
> Acked-by: Morten Brørup <mb at smartsharesystems.com>
> ---
>  MAINTAINERS                            |   5 +
>  app/test/meson.build                   |   2 +
>  app/test/test_pmu.c                    |  62 ++++
>  doc/api/doxy-api-index.md              |   3 +-
>  doc/api/doxy-api.conf.in               |   1 +
>  doc/guides/prog_guide/profile_app.rst  |  12 +
>  doc/guides/rel_notes/release_23_03.rst |   7 +
>  lib/meson.build                        |   1 +
>  lib/pmu/meson.build                    |  13 +
>  lib/pmu/pmu_private.h                  |  32 ++
>  lib/pmu/rte_pmu.c                      | 460 +++++++++++++++++++++++++
>  lib/pmu/rte_pmu.h                      | 212 ++++++++++++
>  lib/pmu/version.map                    |  15 +
>  13 files changed, 824 insertions(+), 1 deletion(-)  create mode 100644
> app/test/test_pmu.c  create mode 100644 lib/pmu/meson.build  create mode 100644
> lib/pmu/pmu_private.h  create mode 100644 lib/pmu/rte_pmu.c  create mode 100644
> lib/pmu/rte_pmu.h  create mode 100644 lib/pmu/version.map
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 3495946d0f..d37f242120 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1697,6 +1697,11 @@ M: Nithin Dabilpuram <ndabilpuram at marvell.com>
>  M: Pavan Nikhilesh <pbhagavatula at marvell.com>
>  F: lib/node/
> 
> +PMU - EXPERIMENTAL
> +M: Tomasz Duszynski <tduszynski at marvell.com>
> +F: lib/pmu/
> +F: app/test/test_pmu*
> +
> 
>  Test Applications
>  -----------------
> diff --git a/app/test/meson.build b/app/test/meson.build index f34d19e3c3..6b61b7fc32
> 100644
> --- a/app/test/meson.build
> +++ b/app/test/meson.build
> @@ -111,6 +111,7 @@ test_sources = files(
>          'test_reciprocal_division_perf.c',
>          'test_red.c',
>          'test_pie.c',
> +        'test_pmu.c',
>          'test_reorder.c',
>          'test_rib.c',
>          'test_rib6.c',
> @@ -239,6 +240,7 @@ fast_tests = [
>          ['kni_autotest', false, true],
>          ['kvargs_autotest', true, true],
>          ['member_autotest', true, true],
> +        ['pmu_autotest', true, true],
>          ['power_cpufreq_autotest', false, true],
>          ['power_autotest', true, true],
>          ['power_kvm_vm_autotest', false, true], diff --git a/app/test/test_pmu.c
> b/app/test/test_pmu.c new file mode 100644 index 0000000000..a64564b5f5
> --- /dev/null
> +++ b/app/test/test_pmu.c
> @@ -0,0 +1,62 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(C) 2023 Marvell International Ltd.
> + */
> +
> +#include "test.h"
> +
> +#ifndef RTE_EXEC_ENV_LINUX
> +
> +static int
> +test_pmu(void)
> +{
> +	printf("pmu_autotest only supported on Linux, skipping test\n");
> +	return TEST_SKIPPED;
> +}
> +
> +#else
> +
> +#include <rte_pmu.h>
> +
> +static int
> +test_pmu_read(void)
> +{
> +	const char *name = NULL;
> +	int tries = 10, event;
> +	uint64_t val = 0;
> +
> +	if (name == NULL) {
> +		printf("PMU not supported on this arch\n");
> +		return TEST_SKIPPED;
> +	}
> +
> +	if (rte_pmu_init() < 0)
> +		return TEST_FAILED;

Can we return TEST_SKIPPED here?
On aarch64, this feature requires kernel version >= 5.17. CI setups doesn't meet this requirement will
start to report failure when running fast_tests.

> +
> +	event = rte_pmu_add_event(name);
> +	while (tries--)
> +		val += rte_pmu_read(event);
> +
> +	rte_pmu_fini();
> +
> +	return val ? TEST_SUCCESS : TEST_FAILED; }
> +
> +static struct unit_test_suite pmu_tests = {
> +	.suite_name = "pmu autotest",
> +	.setup = NULL,
> +	.teardown = NULL,
> +	.unit_test_cases = {
> +		TEST_CASE(test_pmu_read),
> +		TEST_CASES_END()
> +	}
> +};
> +
<snip>