From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8D51F32E12E; Fri, 27 Mar 2026 17:48:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774633688; cv=none; b=k5mULzL9TGKQqeqG3fwzdg15CvofPXngkf8nSIa5VQb4k2IPJlZgXd3m1j+7yJapHic7IhJYpvyTgG2AskOiWkHwIRQGh0qoXeCndE+8x34MAdtERF3TnV1Dwe3H8eYR4lZowH2vzKEBirBMOKQcuqv25OSzRmYNKay3/QZZHFc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774633688; c=relaxed/simple; bh=PGuYUTv91ajLu43m6JZUvnulAqH+tQEuNbaxA3m42h4=; h=From:Date:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=sE7dXyocf/CojGA91siGcrq1goYO8gFZaFk8N/CoLoa+yquu1li3H0kftXX4CweJdVGBe1ggVLofHDSjKZr3+WWB/4z7m7h160qxm+rJB5y5JeCxT0dhbxvPPg1Zm9X/eLHN3G1T/kKo49pf/Hrcd8+6bVj3Ws7Z61CzHe5SVE8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=SThPZKJ9; arc=none smtp.client-ip=192.198.163.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="SThPZKJ9" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1774633687; x=1806169687; h=from:date:to:cc:subject:in-reply-to:message-id: references:mime-version; bh=PGuYUTv91ajLu43m6JZUvnulAqH+tQEuNbaxA3m42h4=; b=SThPZKJ9UAtKryHC/Up2wJsOWf4rk43OsmcZd7OfLbJ35X3FsstbIY0v rW8fqNn3GEgqrXXUt3RVB1Kk9G6qS00AA8dtqMmy6tCkoz1MWnNjVYEQ3 l9XXDrZMVcWkrUMqdqxYhm6D0hJdBYszz8S/mZDn4vsO27APhsNls/fsx DeSn2VbNSQ/B/ugQBzkdokCxRJubvTHqmtnab1eiJAfg+wFzCQRGsEIY1 O84uWjMmZHXVUmROLVJogYbDUJIoQufI2fOP1DZF96Nr8wf/oyVIoYkVN 9Z2OKb9Tz7c0oqs1dEvQryMUIQVE/RQQVQiEzVr46y5UPNrb2+UYwxKGc g==; X-CSE-ConnectionGUID: UCkNw657RwKgypdYxcdj4g== X-CSE-MsgGUID: S34YYHXWQ5CB/8qUhGZ/WQ== X-IronPort-AV: E=McAfee;i="6800,10657,11742"; a="74895966" X-IronPort-AV: E=Sophos;i="6.23,144,1770624000"; d="scan'208";a="74895966" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Mar 2026 10:48:07 -0700 X-CSE-ConnectionGUID: 9htQct0NSY6raxnlgqWadg== X-CSE-MsgGUID: u1s92T/AQDGVolXx+eItfQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,144,1770624000"; d="scan'208";a="248414526" Received: from ijarvine-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.244.186]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Mar 2026 10:48:01 -0700 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 27 Mar 2026 19:47:58 +0200 (EET) To: Reinette Chatre cc: shuah@kernel.org, Dave.Martin@arm.com, james.morse@arm.com, tony.luck@intel.com, babu.moger@amd.com, fenghuay@nvidia.com, peternewman@google.com, zide.chen@intel.com, dapeng1.mi@linux.intel.com, ben.horgan@arm.com, yu.c.chen@intel.com, jason.zeng@intel.com, linux-kselftest@vger.kernel.org, LKML , patches@lists.linux.dev Subject: Re: [PATCH v3 09/10] selftests/resctrl: Simplify perf usage in CAT test In-Reply-To: Message-ID: <2e88c88e-35ef-dc38-5717-f732064f9ab8@linux.intel.com> References: Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="8323328-823094273-1774633678=:1037" This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323328-823094273-1774633678=:1037 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: QUOTED-PRINTABLE On Fri, 13 Mar 2026, Reinette Chatre wrote: > The CAT test relies on the PERF_COUNT_HW_CACHE_MISSES event to determine = if > modifying a cache portion size is successful. This event is configured to > report the data as part of an event group, but no other events are added = to > the group. >=20 > Remove the unnecessary PERF_FORMAT_GROUP format setting. This eliminates > the need for struct perf_event_read and results in read() of the associat= ed > file descriptor to return just one value associated with the > PERF_COUNT_HW_CACHE_MISSES event of interest. >=20 > Signed-off-by: Reinette Chatre > Tested-by: Chen Yu > --- > Changes since v2: > - Add Chen Yu's tag. > --- > tools/testing/selftests/resctrl/cache.c | 17 +++++------------ > tools/testing/selftests/resctrl/cat_test.c | 4 +--- > tools/testing/selftests/resctrl/resctrl.h | 11 +---------- > 3 files changed, 7 insertions(+), 25 deletions(-) >=20 > diff --git a/tools/testing/selftests/resctrl/cache.c b/tools/testing/self= tests/resctrl/cache.c > index bef71b6feacc..df9bea584a2d 100644 > --- a/tools/testing/selftests/resctrl/cache.c > +++ b/tools/testing/selftests/resctrl/cache.c > @@ -10,7 +10,6 @@ void perf_event_attr_initialize(struct perf_event_attr = *pea, __u64 config) > =09memset(pea, 0, sizeof(*pea)); > =09pea->type =3D PERF_TYPE_HARDWARE; > =09pea->size =3D sizeof(*pea); > -=09pea->read_format =3D PERF_FORMAT_GROUP; > =09pea->exclude_kernel =3D 1; > =09pea->exclude_hv =3D 1; > =09pea->exclude_idle =3D 1; > @@ -37,19 +36,13 @@ int perf_event_reset_enable(int pe_fd) > =09return 0; > } > =20 > -void perf_event_initialize_read_format(struct perf_event_read *pe_read) > -{ > -=09memset(pe_read, 0, sizeof(*pe_read)); > -=09pe_read->nr =3D 1; > -} > - > int perf_open(struct perf_event_attr *pea, pid_t pid, int cpu_no) > { > =09int pe_fd; > =20 > =09pe_fd =3D perf_event_open(pea, pid, cpu_no, -1, PERF_FLAG_FD_CLOEXEC)= ; > =09if (pe_fd =3D=3D -1) { > -=09=09ksft_perror("Error opening leader"); > +=09=09ksft_perror("Unable to set up performance monitoring"); > =09=09return -1; > =09} > =20 > @@ -132,9 +125,9 @@ static int print_results_cache(const char *filename, = pid_t bm_pid, __u64 llc_val > * > * Return: =3D0 on success. <0 on failure. > */ > -int perf_event_measure(int pe_fd, struct perf_event_read *pe_read, > -=09=09 const char *filename, pid_t bm_pid) > +int perf_event_measure(int pe_fd, const char *filename, pid_t bm_pid) > { > +=09__u64 value; > =09int ret; > =20 > =09/* Stop counters after one span to get miss rate */ > @@ -142,13 +135,13 @@ int perf_event_measure(int pe_fd, struct perf_event= _read *pe_read, > =09if (ret < 0) > =09=09return ret; > =20 > -=09ret =3D read(pe_fd, pe_read, sizeof(*pe_read)); > +=09ret =3D read(pe_fd, &value, sizeof(value)); > =09if (ret =3D=3D -1) { > =09=09ksft_perror("Could not get perf value"); > =09=09return -1; > =09} > =20 > -=09return print_results_cache(filename, bm_pid, pe_read->values[0].value= ); > +=09return print_results_cache(filename, bm_pid, value); > } > =20 > /* > diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/s= elftests/resctrl/cat_test.c > index 8bc47f06679a..6aac03147d41 100644 > --- a/tools/testing/selftests/resctrl/cat_test.c > +++ b/tools/testing/selftests/resctrl/cat_test.c > @@ -135,7 +135,6 @@ static int cat_test(const struct resctrl_test *test, > =09=09 struct resctrl_val_param *param, > =09=09 size_t span, unsigned long current_mask) > { > -=09struct perf_event_read pe_read; > =09struct perf_event_attr pea; > =09cpu_set_t old_affinity; > =09unsigned char *buf; > @@ -159,7 +158,6 @@ static int cat_test(const struct resctrl_test *test, > =09=09goto reset_affinity; > =20 > =09perf_event_attr_initialize(&pea, PERF_COUNT_HW_CACHE_MISSES); > -=09perf_event_initialize_read_format(&pe_read); > =09pe_fd =3D perf_open(&pea, bm_pid, uparams->cpu); > =09if (pe_fd < 0) { > =09=09ret =3D -1; > @@ -192,7 +190,7 @@ static int cat_test(const struct resctrl_test *test, > =20 > =09=09=09fill_cache_read(buf, span, true); > =20 > -=09=09=09ret =3D perf_event_measure(pe_fd, &pe_read, param->filename, bm= _pid); > +=09=09=09ret =3D perf_event_measure(pe_fd, param->filename, bm_pid); > =09=09=09if (ret) > =09=09=09=09goto free_buf; > =09=09} > diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/se= lftests/resctrl/resctrl.h > index 3bad2d80c09b..175101022bf3 100644 > --- a/tools/testing/selftests/resctrl/resctrl.h > +++ b/tools/testing/selftests/resctrl/resctrl.h > @@ -148,13 +148,6 @@ struct resctrl_val_param { > =09struct fill_buf_param=09*fill_buf; > }; > =20 > -struct perf_event_read { > -=09__u64 nr;=09=09=09/* The number of events */ > -=09struct { > -=09=09__u64 value;=09=09/* The value of the event */ > -=09} values[2]; > -}; > - > /* > * Memory location that consumes values compiler must not optimize away. > * Volatile ensures writes to this location cannot be optimized away by > @@ -210,11 +203,9 @@ unsigned int count_bits(unsigned long n); > int snc_kernel_support(void); > =20 > void perf_event_attr_initialize(struct perf_event_attr *pea, __u64 confi= g); > -void perf_event_initialize_read_format(struct perf_event_read *pe_read); > int perf_open(struct perf_event_attr *pea, pid_t pid, int cpu_no); > int perf_event_reset_enable(int pe_fd); > -int perf_event_measure(int pe_fd, struct perf_event_read *pe_read, > -=09=09 const char *filename, pid_t bm_pid); > +int perf_event_measure(int pe_fd, const char *filename, pid_t bm_pid); > int measure_llc_resctrl(const char *filename, pid_t bm_pid); > int minimize_l2_occupancy(const struct resctrl_test *test, > =09=09=09 const struct user_params *uparams, >=20 Reviewed-by: Ilpo J=E4rvinen --=20 i. --8323328-823094273-1774633678=:1037--